add install only option

Author: mikulicf

action.yml

@@ -8,6 +8,10 @@ inputs:
     description: "Platform to build for"
     required: false
     default: "true"
+  install_only:
+    description: "Only install wails"
+    required: false
+    default: "false"
   sign:
     description: "Sign the build"
     required: false
@@ -136,15 +140,15 @@ runs:
         install-only: true
     # install wails
     - name: Install Wails
-      if: inputs.build == 'true'
+      if: inputs.build == 'true' || install_only == 'true'
       run: go install github.com/wailsapp/wails/v2/cmd/wails@${{inputs.wails-version}}
       shell: bash
     - name: Install Linux Wails deps
-      if: inputs.build == 'true' && runner.os == 'Linux'
+      if: inputs.build == 'true' && runner.os == 'Linux' || install_only == 'true' && runner.os == 'Linux'
       run: sudo apt-get update && sudo apt-get install libgtk-3-0 libwebkit2gtk-4.0-dev gcc-aarch64-linux-gnu
       shell: bash
     - name: Install macOS Wails deps
-      if: runner.os == 'macOS'
+      if: runner.os == 'macOS' || install_only == 'true' && runner.os == 'macOS'
       run: brew install mitchellh/gon/gon
       shell: bash
     # Building step