CI/CD: Use vesc_tool 6.06 for building

Uses the new --buildPkgFromDesc, which checks compatibility before
installing.

Author: lukash

.github/actions/build/action.yml

@@ -15,8 +15,8 @@ runs:
         authToken: '${{ inputs.cache-auth-token }}'
     - uses: rrbutani/use-nix-shell-action@v1
       with:
-        flakes: nixpkgs/nixos-24.11#gcc-arm-embedded-7, nixpkgs#gnumake, github:lukash/vesc_tool-flake/release_6_05
+        flakes: nixpkgs/nixos-24.11#gcc-arm-embedded-7, nixpkgs#gnumake, github:lukash/vesc_tool-flake/release_6_06
 
     - name: Build
       shell: bash
-      run: make -j OLDVT=1
+      run: make -j