proper GH variable setting

sources/manager_environment.py

@@ -48,5 +48,8 @@ class EnvironmentManager:
     DEBUG_RUN = getenv("DEBUG_RUN", "False").lower() in _TRUTHY
 
     @staticmethod
-    def set_variable(name: str, content: str):
-        environ[name] = content
+    def set_github_output(name: str, content: str):
+        if "GITHUB_OUTPUT" not in environ.keys():
+            raise Exception("Not in GitHub environment ('GITHUB_OUTPUT' not defined)!")
+        with open(environ["GITHUB_OUTPUT"], "a") as fh:
+            fh.write(f"{name}={content}")

sources/manager_github.py

@@ -110,7 +110,7 @@ class GitHubManager:
         """
         prefix = "README stats current output:"
         DBM.i("Commenting PR...")
-        EM.set_variable("GITHUB_OUTPUT", f"README_CONTENT={prefix}\n\n{stats}")
+        EM.set_github_output("README_CONTENT", f"{prefix}\n\n{stats}")
         DBM.g("PR commented!")
 
     @staticmethod