Update setup-emsdk from v13 to v14

I've been running into issues when multiple runners attempt to use the emsdk cache because the key is the same.
 
This has been addressed in v14: https://github.com/mymindstorm/setup-emsdk/releases/tag/v14

There should be no reason not to upgrade.

.github/actions/build/action.yml

@@ -67,7 +67,7 @@ runs:
 # Web only
     - name: Web - Set up Emscripten latest
       if: ${{ inputs.platform == 'web' }}
-      uses: mymindstorm/setup-emsdk@v13
+      uses: mymindstorm/setup-emsdk@v14
       with:
         version: ${{ inputs.em_version }}
         actions-cache-folder: ${{ inputs.em-cache-directory }}.${{ inputs.float-precision }}.${{ inputs.build-target-type }}