Add monthly contributors report (InnerSourceCommons#602)

* Add workflow that will create a monthly report of contributors to this repo

Author: spier

.github/workflows/contributor-report.yaml

@@ -0,0 +1,47 @@
+name: "Monthly Metrics: Contributors"
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: '3 2 1 * *'
+
+permissions:
+  issues: write
+
+jobs:
+  contributor_report:
+    name: contributor report
+    runs-on: ubuntu-latest
+
+    steps:
+
+    - name: Get dates for last month
+      shell: bash
+      run: |
+        # Calculate the first day of the previous month
+        start_date=$(date -d "last month" +%Y-%m-01)
+
+        # Calculate the last day of the previous month
+        end_date=$(date -d "$start_date +1 month -1 day" +%Y-%m-%d)
+
+        # Set an environment variable with the date range
+        echo "START_DATE=$start_date" >> "$GITHUB_ENV"
+        echo "END_DATE=$end_date" >> "$GITHUB_ENV"
+
+    - name: Run contributor action
+      uses: github/contributors@v1
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        START_DATE: ${{ env.START_DATE }}
+        END_DATE: ${{ env.END_DATE }}
+        REPOSITORY: InnerSourceCommons/InnerSourcePatterns
+        SPONSOR_INFO: "true"
+
+    - name: Create issue
+      uses: peter-evans/create-issue-from-file@v4
+      with:
+        title: "Monthly Metrics: Contributors"
+        token: ${{ secrets.GITHUB_TOKEN }}
+        content-filepath: ./contributors.md
+        assignees: spier
+        labels: |
+          community metrics