feat: add submodule workaround script and update build command in vercel.json

.vercel/submodule-workaround.sh

@@ -0,0 +1,39 @@
+# github submodule repo address without https:// prefix
+SUBMODULE_GITHUB=github.com/primefaces/sakai-assets.git
+
+# .gitmodules submodule path
+SUBMODULE_PATH=src/assets
+
+# github access token is necessary
+# add it to Environment Variables on Vercel
+if [ "$GITHUB_ACCESS_TOKEN" == "" ]; then
+  echo "Error: GITHUB_ACCESS_TOKEN is empty"
+  exit 1
+fi
+
+# stop execution on error - don't let it build if something goes wrong
+set -e
+
+# get submodule commit
+output=`git submodule status --recursive` # get submodule info
+no_prefix=${output#*-} # get rid of the prefix
+COMMIT=${no_prefix% *} # get rid of the suffix
+
+# set up an empty temporary work directory
+rm -rf tmp || true # remove the tmp folder if exists
+mkdir tmp # create the tmp folder
+cd tmp # go into the tmp folder
+
+# checkout the current submodule commit
+git init # initialise empty repo
+git remote add origin https://$GITHUB_ACCESS_TOKEN@$SUBMODULE_GITHUB # add origin of the submodule
+git fetch --depth=1 origin $COMMIT # fetch only the required version
+git checkout $COMMIT # checkout on the right commit
+
+# move the submodule from tmp to the submodule path
+cd .. # go folder up
+rm -rf tmp/.git # remove .git 
+mv tmp/* $SUBMODULE_PATH/ # move the submodule to the submodule path
+
+# clean up
+rm -rf tmp # remove the tmp folder

vercel.json

@@ -5,5 +5,6 @@
             "destination": "/index.html"
         }
     ],
-    "trailingSlash": false
+    "trailingSlash": false,
-}
+    "buildCommand": "bash .vercel/submodule-workaround.sh && npm run build"
+}