ci: fix msrv dependency versions for reqest and h2

- reqwest 0.11.19 has MSRV 1.63.0+, pin to 0.11.18
- h2 0.3.21 has MSRV 1.63.0+, pin to 0.3.20

.github/workflows/cont_integration.yml

@@ -35,6 +35,8 @@ jobs:
           cargo update -p rustls:0.21.6 --precise "0.21.1"
           cargo update -p tokio:1.32.0 --precise "1.29.1"
           cargo update -p flate2:1.0.27 --precise "1.0.26"
+          cargo update -p reqwest --precise "0.11.18"
+          cargo update -p h2 --precise "0.3.20"
       - name: Build
         run: cargo build ${{ matrix.features }}
       - name: Test