ci: assigner: add module and issue support, enable issue

Add a scheduled entry to run_assignee to run the module assignment
function periodically, as well as a target to run the issue code when
issue labels are changed.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

.github/workflows/assigner.yml

@@ -10,6 +10,9 @@ on:
     branches:
     - main
     - v*-branch
+  issues:
+    types:
+    - labeled
 
 jobs:
   assignment:
@@ -21,7 +24,7 @@ jobs:
     - name: Install Python dependencies
       run: |
         sudo pip3 install -U setuptools wheel pip
-        pip3 install -U PyGithub>=1.55
+        pip3 install -U PyGithub>=1.55 west
 
     - name: Check out source code
       uses: actions/checkout@v3
@@ -30,9 +33,19 @@ jobs:
       env:
         GITHUB_TOKEN: ${{ secrets.ZB_GITHUB_TOKEN }}
       run: |
-        python3 scripts/set_assignees.py \
-          -v \
-          -o ${{ github.event.repository.owner.login }} \
-          -r ${{ github.event.repository.name }} \
-          -M MAINTAINERS.yml \
-          -P ${{ github.event.pull_request.number }}
+        FLAGS="-v"
+        FLAGS+=" -o ${{ github.event.repository.owner.login }}"
+        FLAGS+=" -r ${{ github.event.repository.name }}"
+        FLAGS+=" -M MAINTAINERS.yml"
+        if [ "${{ github.event_name }}" = "pull_request_target" ]; then
+            FLAGS+=" -P ${{ github.event.pull_request.number }}"
+        elif [ "${{ github.event_name }}" = "issues" ]; then
+            FLAGS+=" -I ${{ github.event.issue.number }}"
+        elif [ "${{ github.event_name }}" = "schedule" ]; then
+            FLAGS+=" --modules"
+        else
+          echo "Unknown event: ${{ github.event_name }}"
+          exit 1
+        endif
+
+        python3 scripts/set_assignees.py $FLAGS