Update images, fix extrapath (#723)

* fix: typo

* fix: remove debug for git references

it generates a massive amount of logs

* feat: read values from env

allows to test act on GHA when it's not a main repo

* fix: merge extrapath with PATH

* fix(tests): add additional shells for testing

* fix(image): update images

pin node to major version only, current node version: 12.22.1
replace most images with `node:12-buster-slim` to prevent
errors on macOS runner due to DockerHub pull limit
replace ocaml image

Co-authored-by: Casey Lee <cplee@nektos.com>

pkg/runner/testdata/job-container/push.yml

@@ -4,8 +4,8 @@ on: push
 jobs:
   test:
     runs-on: ubuntu-latest
-    container: 
-      image: node:12.20.1-buster
+    container:
+      image: node:12-buster-slim
       env:
         TEST_ENV: test-value
     steps:
@@ -13,7 +13,7 @@ jobs:
 
   test2:
     runs-on: ubuntu-latest
-    container: node:12.20.1-buster
+    container: node:12-buster-slim
     steps:
       - run: echo ${TEST_ENV} | grep test-value
         env: