Action: Support running in a docker container
diff --git a/CHANGES.md b/CHANGES.md
index cb637d94c11..a687f3090bf 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -22,6 +22,10 @@
 
 - All upper version bounds on dependencies have been removed (#2718)
 
+### Integrations
+
+- Update GitHub action to support containerized runs (#2748)
+
 ## 21.12b0
 
 ### _Black_
diff --git a/action.yml b/action.yml
index ddf07933a3e..dd2de1b62ad 100644
--- a/action.yml
+++ b/action.yml
@@ -38,7 +38,7 @@ runs:
         import subprocess;
         from pathlib import Path;
 
-        MAIN_SCRIPT = Path(r'${{ github.action_path }}') / 'action' / 'main.py';
+        MAIN_SCRIPT = Path(r'${GITHUB_ACTION_PATH}') / 'action' / 'main.py';
 
         proc = subprocess.run([sys.executable, str(MAIN_SCRIPT)]);
         sys.exit(proc.returncode)

`${{ github.action_path }}` doesn't point to the correct path when run in a docker container, you have to use the environmental variable `GITHUB_ACTION_PATH` 

https://github.com/actions/runner/issues/716

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