Add workflow to create pull requests with cpanfile.snapshot updates

Author: oalders

.github/workflows/update-snapshot.yml

@@ -0,0 +1,35 @@
+name: Update cpanfile.snapshot
+on:
+    schedule:
+        - cron: "1 15 * * 0"
+    workflow_dispatch:
+jobs:
+    update-dep:
+        runs-on: "ubuntu-20.04"
+        steps:
+            - uses: actions/checkout@v2
+            - name: Install Carton
+              run: >
+                  curl -sL https://git.io/cpm | perl -
+                  install -g Carton
+                  --show-build-log-on-failure
+            - name: Install deps
+              run: >
+                  curl -sL https://git.io/cpm | perl -
+                  install
+                  --cpanfile cpanfile
+                  --resolver metacpan
+                  --show-build-log-on-failure
+                  --local-lib-contained=local
+            - name: Maybe update cpanfile.snapshot
+              run: carton
+            - name: Create Pull Request
+              uses: peter-evans/create-pull-request@v3
+              with:
+                  commit-message: Update cpanfile.snapshot
+                  title: Update cpanfile.snapshot
+                  body: |
+                      Auto-generated by [create-pull-request][1]
+
+                      [1]: https://github.com/peter-evans/create-pull-request
+                  branch: update-cpanfile-snapshot