Add Setup Environment step to publish workflows (#351)

Adds the missing `Setup Environment` step to the `set_env` job of the
publish-js and publish-rust workflows so `toml-cli` is available when
computing the Solana CLI version. Without it, `make solana-cli-version`
returned an empty value, which made the Solana install target a malformed
URL and fail on a cold cache.

Author: lorisleiva

.github/workflows/publish-js.yml

@@ -46,6 +46,9 @@ jobs:
       - name: Git Checkout
         uses: actions/checkout@v4
 
+      - name: Setup Environment
+        uses: solana-program/actions/setup-ubuntu@main
+
       - name: Compute variables
         id: compute
         shell: bash

.github/workflows/publish-rust.yml

@@ -51,6 +51,9 @@ jobs:
       - name: Git Checkout
         uses: actions/checkout@v4
 
+      - name: Setup Environment
+        uses: solana-program/actions/setup-ubuntu@main
+
       - name: Compute variables
         id: compute
         shell: bash