FIX Ensure nvmdir exists (#42)

action.yml

@@ -205,6 +205,11 @@ runs:
         fi
         # Set nvmdir explicitly before installation. Default dir doesn't work for some reason.
         export NVM_DIR="${HOME}/.nvm"
+        # Installation fails if install dir is specified but doesn't exist
+        if ! [[ -d "$NVM_DIR" ]]; then
+          echo "NVM_DIR '$NVM_DIR' doesn't exist - creating it now"
+          mkdir $NVM_DIR
+        fi
         # Remove any sneaky attempts to put __install-nvm.sh into pull-requests
         if [[ -f __install-nvm.sh ]]; then
           rm __install-nvm.sh
@@ -218,7 +223,7 @@ runs:
           exit 1
         fi
         # this loads nvm into the current terminal
-        [[ -s "$NVM_DIR/nvm.sh" ]] && \. "$NVM_DIR/nvm.sh"
+        [[ -s "$NVM_DIR/nvm.sh" ]] && \. "$NVM_DIR/nvm.sh" --no-use
         ADMIN_NPM_VERSION=
         if [[ -d vendor/silverstripe/admin ]]; then
           cd vendor/silverstripe/admin