Add GitHub Action to require size and kind labels (#4876)

* Add GitHub Action to require size and kind labels

Currently there is no enforcement of adding `size/*` or `kind/*` labels
to issues. This will help the project and collaborators understand the
type of issue, as well as a rough estimate of how long it is projected
to take to resolve.

This PR adds the workflow to mark issues with `size/needed` in the
absence of `size/*` labels, and `kind/needed` in the absence of `kind/*`
labels. This will only consider issues that are part of a milestone.

Signed-off-by: Thomas Stringer <[email protected]>

* Fix typo for configuration setting

Signed-off-by: Thomas Stringer <[email protected]>

Author: trstringer

.github/workflows/require-labels.yml

@@ -0,0 +1,26 @@
+name: Require labels
+on:
+  schedule:
+    - cron: "0 0 * * *"
+
+jobs:
+  labels:
+    name: Require labels
+    runs-on: ubuntu-latest
+    steps:
+      - name: Require size
+        uses: trstringer/require-label-prefix@v1
+        with:
+          secret: ${{ github.TOKEN }}
+          prefix: size
+          addLabel: true
+          defaultLabel: "size/needed"
+          onlyMilestone: true
+      - name: Require kind
+        uses: trstringer/require-label-prefix@v1
+        with:
+          secret: ${{ github.TOKEN }}
+          prefix: kind
+          addLabel: true
+          defaultLabel: "kind/needed"
+          onlyMilestone: true