add manual run; add build type to GH actions

.github/workflows/tarball.yml

@@ -3,13 +3,17 @@ name: dvmhost-build-tarball
 # Controls when the workflow will run
 on:
   # Allows you to run this workflow manually from the Actions tab
-  #workflow_dispatch:
+  workflow_dispatch:
   #run on push/PR
   push:
     branches: [ master ]
   pull_request:
     branches: [ master ]
 
+env:
+  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
+  BUILD_TYPE: Release
+
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
   # This workflow contains a single job called "build"