GitHub CI: add workflow_dispatch trigger

Author: ds-sloth

.github/workflows/macos-ci.yml

@@ -8,6 +8,7 @@ on:
   pull_request:
     branches:
       - master
+  workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}

.github/workflows/ubuntu-ci.yml

@@ -9,6 +9,7 @@ on:
   pull_request:
     branches:
       - master
+  workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}

.github/workflows/windows-ci.yml

@@ -8,6 +8,7 @@ on:
   pull_request:
     branches:
       - master
+  workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}