Fix resolving check-dir when changing working-directory

* Should fix r-lib#614, at least for the typical case where `check-dir` is a relative path.
* `check-dir` is now resolved relative to the working directory, as absolute path to also make it independent of the working directory of subsequent steps were the resolved `check-dir-path` output is used.

check-r-package/action.yaml

@@ -35,7 +35,7 @@ runs:
         ## --------------------------------------------------------------------
         options(crayon.enabled = TRUE)
         if (Sys.getenv("_R_CHECK_FORCE_SUGGESTS_", "") == "") Sys.setenv("_R_CHECK_FORCE_SUGGESTS_" = "false")
-        cat("##[set-output name=check-dir-path;]", (${{ inputs.check-dir }}), "\n", sep = "")
+        cat("##[set-output name=check-dir-path;]", file.path(getwd(), (${{ inputs.check-dir }})), "\n", sep = "")
         check_results <- rcmdcheck::rcmdcheck(args = (${{ inputs.args }}), build_args = (${{ inputs.build_args }}), error_on = (${{ inputs.error-on }}), check_dir = (${{ inputs.check-dir }}))
       shell: Rscript {0}
       working-directory: ${{ inputs.working-directory }}