fix: always get latest pnpm (#4571)

Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>

.gitpod.yml

@@ -3,7 +3,11 @@ image:
   file: .Dockerfile
 # Commands to start on workspace startup
 tasks:
-  - init: |
+  - before: |
+      # Get latest pnpm version, in case the custom docker image was not updated
+      # Until this issue gets resolved - https://github.com/gitpod-io/gitpod/issues/12551
+      curl -fsSL https://get.pnpm.io/install.sh | SHELL=`which bash` bash -
+    init: |
       pnpm install
       pnpm run build
     command: |