bump twoxtx ci rust version to 1.72.0 (#5218)

Author: Joe C

.github/workflows/pull-request-token.yml

@@ -214,7 +214,7 @@ jobs:
 
       - name: Set env vars
         run: |
-          echo "RUST_STABLE_VERSION=1.69.0" >> $GITHUB_ENV
+          echo "RUST_STABLE_VERSION=1.72.0" >> $GITHUB_ENV
           source ci/rust-version.sh
           echo "RUST_STABLE=$rust_stable" >> $GITHUB_ENV
           source ci/solana-version.sh