Add workflow dispatch

Author: jodastephen

.github/workflows/build.yml

@@ -12,6 +12,7 @@ on:
   pull_request:
     branches:
       - 'main'
+  workflow_dispatch:
 
 permissions:
   contents: read

.github/workflows/tzdbupdate.yml

@@ -6,6 +6,7 @@ on:
       - 'tzdb*'
   schedule:
     - cron: '50 1 * * *'
+  workflow_dispatch:
 
 permissions:
   contents: read