ci: Remove jobserver pin

It is not needed anymore. Discovered in #1344

Author: danielabrozzoni

.github/workflows/cont_integration.yml

@@ -32,7 +32,6 @@ jobs:
         run: |
           cargo update -p zstd-sys --precise "2.0.8+zstd.1.5.5"
           cargo update -p time --precise "0.3.20"
-          cargo update -p jobserver --precise "0.1.26"
           cargo update -p home --precise "0.5.5"
       - name: Build
         run: cargo build ${{ matrix.features }}