.github: add correct changelog

Changelog directory is now located under flatcar scripts, not under
coreos overlay. Fix the location to add correct changelog to the git
commit.

Also use a correct path SDK_OUTER_TOPDIR in cleanup_repo.

.github/workflows/common.sh

@@ -173,12 +173,17 @@ function commit_changes() {
 
   regenerate_manifest "${pkg}" "${new_version}"
 
-  pushd "${SDK_OUTER_OVERLAY}"
+  pushd "${SDK_OUTER_TOPDIR}"
 
-  git add "${pkg}"
   if [[ -d changelog ]]; then
     git add changelog
   fi
+
+  popd
+
+  pushd "${SDK_OUTER_OVERLAY}"
+
+  git add "${pkg}"
   for dir; do
     git add "${dir}"
   done
@@ -193,7 +198,7 @@ function commit_changes() {
 # avoid unwanted changes to be a part of a PR created by the
 # peter-evans/create-pull-request action that follows up.
 function cleanup_repo() {
-    git -C "${SDK_OUTER_OVERLAY}" status
-    git -C "${SDK_OUTER_OVERLAY}" reset --hard HEAD
-    git -C "${SDK_OUTER_OVERLAY}" clean -ffdx
+    git -C "${SDK_OUTER_TOPDIR}" status
+    git -C "${SDK_OUTER_TOPDIR}" reset --hard HEAD
+    git -C "${SDK_OUTER_TOPDIR}" clean -ffdx
 }