fix invalid syntax (?)

Author: umbynos

.github/workflows/release.yml

@@ -148,7 +148,7 @@ jobs:
     env:
       # vars used by installbuilder
       INSTALLBUILDER_VERSION: 20.0.9
-      INSTALLBUILDER_PATH: "/opt/installbuilder-${{ INSTALLBUILDER_VERSION }}/bin/builder"
+      INSTALLBUILDER_PATH: "/opt/installbuilder-${{ env.INSTALLBUILDER_VERSION }}/bin/builder"
       INSTALLER_VARS: "project.outputDirectory=$PWD project.version=${GITHUB_REF##*/} workspace=$PWD realname=Arduino_Create_Bridge"
       # vars passed to installbuilder to install https certs automatically
       CERT_INSTALL: "ask_certificates_install=CI"  # win(edge),mac(safari)