main removed $RR from crystal build command

The github action for release was failing because it did
not know the correct value of the envar RR which
locally us set by the direnv utility via the .envrc file.

crystal/justfile

@@ -5,6 +5,8 @@
 #   https://github.com/casey/just
 #
 
+repo_root := "$PWD/.."
+
 
 # List available recipes
 @help:
@@ -16,7 +18,6 @@
   just -l --list-prefix 'just ' --list-heading ''
   echo
 
-
 alias compile := build
 
 # static builds only work on linux (and only if you have the dev libraries installed)
@@ -27,7 +28,7 @@ extra_build_args := if join(os(), static) == "linux/true" { "--static" } else {
 # Builds the crystal version of justprep
 build: _make_bin
   crystal build {{extra_build_args}} --no-debug --release -p -o bin/justprep \
-    $RR/ruby/lib/justprep/common/*.crb \
+    {{repo_root}}/ruby/lib/justprep/common/*.crb \
     justprep.cr