CI: Also run Cygwin CI when workflow changed.

Author: DWesl

.github/workflows/cygwin.yml

@@ -13,6 +13,7 @@ on:
       - v*
     paths:
       - 'src/**'
+      - '.github/workflows/cygwin.yml'
   pull_request:
     types:
       - opened
@@ -23,6 +24,7 @@ on:
       - v[0-9]+.[0-9]+.[0-9x]+-doc
     paths:
       - 'src/**'
+      - '.github/workflows/cygwin.yml'
   schedule:
     # 5:47 UTC on Saturdays
     - cron: "47 5 * * 6"