ci: ensure man page is up to date (#166)

Author: NickLarsenNZ

.github/workflows/pr_stackablectl.yml

@@ -71,3 +71,9 @@ jobs:
         run: |
           cargo xtask gen-comp
           git diff --exit-code
+
+      - name: Ensure man page is up-to-date
+        if: matrix.os = 'x86_64-unknown-linux-gnu'
+        run: |
+          cargo xtask gen-man
+          git diff --exit-code