Use default branch of `psvm` when synchronizing templates (#4240)

We cannot lock to a specific version of `psvm`, because we will need to
keep it up-to-date - each release currently requires a change in `psvm`
such as [this one](https://github.com/paritytech/psvm/pull/2/files).

There is no `stable` branch in `psvm` repo or anything so using the
default branch.

.github/workflows/sync-templates.yml

@@ -61,7 +61,7 @@ jobs:
       - name: Install toml-cli
         run: cargo install --git https://github.com/gnprice/toml-cli --rev ea69e9d2ca4f0f858110dc7a5ae28bcb918c07fb # v0.2.3
       - name: Install Polkadot SDK Version Manager
-        run: cargo install --git https://github.com/paritytech/psvm --rev c41261ffb52ab0c115adbbdb17e2cb7900d2bdfd psvm # master
+        run: cargo install --git https://github.com/paritytech/psvm psvm
       - name: Rust compilation prerequisites
         run: |
           sudo apt update