Add set_summary helper function

post/clang_tidy_review/clang_tidy_review/__init__.py

@@ -961,7 +961,7 @@ def create_review(
     # Post to the action job summary
     step_summary = "summary"
     # step_summary += make_timing_summary(clang_tidy_profiling)
-    set_output("GITHUB_STEP_SUMMARY", step_summary)
+    set_summary(step_summary)
 
     print("clang-tidy had the following warnings:\n", clang_tidy_warnings, flush=True)
 
@@ -1179,6 +1179,17 @@ def set_output(key: str, val: str) -> bool:
     return True
 
 
+def set_summary(val: str) -> bool:
+    if "GITHUB_STEP_SUMMARY" not in os.environ:
+        return False
+
+    # append key-val pair to file
+    with open(os.environ["GITHUB_STEP_SUMMARY"], "a") as f:
+        f.write(val)
+
+    return True
+
+
 def decorate_comment_body(comment: str) -> str:
     """
     Split on first dash into two groups of string in [] at end of line