[WIP] Resurrect CI

[jbodah]

This PR is an attempt to get CI working again (using GH Actions to kickoff docker builds)

[jbodah]

Currently having test start but hang in the container; need to debug further

[jbodah]

Issue is related to reads blocking

[jbodah]

Looks like the vim instance spun up by vimrunner is in an async read loop and not responding to rspec. Here's how the vim instance was booted:

root@5ab06d4bacd9:/var/vim-elixir# ps aux | grep vim
root       884  0.8  0.8 182376 18184 ?        Ss+  02:15   0:01 vim -f --servername VIMRUNNER0.6564163204254299 -u /var/lib/gems/2.5.0/gems/vimrunner-0.3.4/vim/vimrc -U NONE -i NONE --noplugin
root      1081 31.0  0.6 170512 12440 pts/0    S+   02:15   0:43 vim --servername VIMRUNNER0.6564163204254299 --remote-expr VimrunnerEvaluateCommandOutput('cd /tmp/d20200311-881-zdltaw')
root      1117  0.0  0.0  11464  1024 pts/0    S+   02:18   0:00 grep --color=auto vim

and vim --version:

VIM - Vi IMproved 8.0 (2016 Sep 12, compiled Jun 06 2019 17:31:41)
Included patches: 1-1453
Modified by pkg-vim-maintainers@lists.alioth.debian.org
Compiled by pkg-vim-maintainers@lists.alioth.debian.org
Huge version with GTK2 GUI.  Features included (+) or not (-):
+acl               +farsi             +mouse_sgr         -tag_any_white
+arabic            +file_in_path      -mouse_sysmouse    +tcl
+autocmd           +find_in_path      +mouse_urxvt       +termguicolors
-autoservername    +float             +mouse_xterm       +terminal
+balloon_eval      +folding           +multi_byte        +terminfo
+balloon_eval_term -footer            +multi_lang        +termresponse
+browse            +fork()            -mzscheme          +textobjects
++builtin_terms    +gettext           +netbeans_intg     +timers
+byte_offset       -hangul_input      +num64             +title
+channel           +iconv             +packages          +toolbar
+cindent           +insert_expand     +path_extra        +user_commands
+clientserver      +job               +perl              +vertsplit
+clipboard         +jumplist          +persistent_undo   +virtualedit
+cmdline_compl     +keymap            +postscript        +visual
+cmdline_hist      +lambda            +printer           +visualextra
+cmdline_info      +langmap           +profile           +viminfo
+comments          +libcall           -python            +vreplace
+conceal           +linebreak         +python3           +wildignore
+cryptv            +lispindent        +quickfix          +wildmenu
+cscope            +listcmds          +reltime           +windows
+cursorbind        +localmap          +rightleft         +writebackup
+cursorshape       +lua               +ruby              +X11
+dialog_con_gui    +menu              +scrollbind        -xfontset
+diff              +mksession         +signs             +xim
+digraphs          +modify_fname      +smartindent       +xpm
+dnd               +mouse             +startuptime       +xsmp_interact
-ebcdic            +mouseshape        +statusline        +xterm_clipboard
+emacs_tags        +mouse_dec         -sun_workshop      -xterm_save
+eval              +mouse_gpm         +syntax
+ex_extra          -mouse_jsbterm     +tag_binary
+extra_search      +mouse_netterm     +tag_old_static
   system vimrc file: "$VIM/vimrc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
  system gvimrc file: "$VIM/gvimrc"
    user gvimrc file: "$HOME/.gvimrc"
2nd user gvimrc file: "~/.vim/gvimrc"
       defaults file: "$VIMRUNTIME/defaults.vim"
    system menu file: "$VIMRUNTIME/menu.vim"
  fall-back for $VIM: "/usr/share/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_GTK  -pthread -I/usr/include/gtk-2.0 -I/usr/lib/x86_64-linux-gnu/gtk-2.0/include -I/usr/include/gio-unix-2.0/ -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/freetype2 -I/usr/include/libpng16 -I/usr/include/freetype2 -I/usr/include/libpng16 -Wdate-time  -g -O2 -fdebug-prefix-map=/build/vim-8l5tlu/vim-8.0.1453=. -fstack-protector-strong -Wformat -Werror=format-security -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -L. -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fstack-protector -rdynamic -Wl,-export-dynamic -Wl,-E  -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -o vim   -lgtk-x11-2.0 -lgdk-x11-2.0 -lpangocairo-1.0 -latk-1.0 -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lpangoft2-1.0 -lpango-1.0 -lgobject-2.0 -lglib-2.0 -lfontconfig -lfreetype -lSM -lICE -lXpm -lXt -lX11 -lXdmcp -lSM -lICE  -lm -ltinfo -lnsl  -lselinux  -lacl -lattr -lgpm -ldl  -L/usr/lib -llua5.2 -Wl,-E  -fstack-protector-strong -L/usr/local/lib  -L/usr/lib/x86_64-linux-gnu/perl/5.26/CORE -lperl -ldl -lm -lpthread -lcrypt  -L/usr/lib/python3.6/config-3.6m-x86_64-linux-gnu -lpython3.6m -lpthread -ldl -lutil -lm -L/usr/lib/x86_64-linux-gnu -ltcl8.6 -ldl -lz -lpthread -lm -lruby-2.5 -lpthread -lgmp -ldl -lcrypt -lm