readme: use checks for bullet points (#117)

README.md

@@ -17,20 +17,20 @@ There are four key packages,
 
 ### Changes
 
-:crown: v0.6.0 adds support for custom `cmp.Option` values
+:ballot_box_with_check: v0.6.0 adds support for custom `cmp.Option` values
 
  - Adds ability to customize cmp.Equal behavior via cmp.Option arguments
  - Adds assertions for existence of single map key
  - Fixes some error outputs
 
-:rocket: v0.5.0 contains new packages `wait` and `portal`
+:ballot_box_with_check: v0.5.0 contains new packages `wait` and `portal`
 
  - Package for waiting on conditionals
  - Package for allocating free ports
  - Additional Map assertions
  - Additional `Not*` assertion variants
 
-:warning: v0.4.0 contains breaking changes
+:ballot_box_with_check: v0.4.0 contains breaking changes
 
  - Slice functions are renamed to be more consistent and to make room for interface based variants.
  - Filesystem assertions now use OS by default, FS interface methods are renamed.