Merge #86: CI: Pin serde_json for MSRV build

f2fd85c CI: Pin serde_json for MSRV build (Tobin C. Harding)

Pull request description:

  Recent release of `serde_json` depends on `serde` 1.0.66 but we pin to 1.0.56

  Pin `serde_json` for MSRV build to v1.0.99

ACKs for top commit:
  danielabrozzoni:
    ACK f2fd85c

Tree-SHA512: 68f371d010f7ce4d97c7073e7e5bb3a71689eb46be6bd00d6afecc1d0bf40de90bd1d77c064f7134223f0cd5245797c7896f00b8c23c737abd8366ba9a86440f

Author: danielabrozzoni

.github/workflows/main.yml

@@ -87,8 +87,10 @@ jobs:
       - if: ${{matrix.rust.version}} = 1.48.0
         name: Pin dependencies that use edition 2021
         # serde 1.0.157 uses syn 2.0 which requires edition 2021.
+        # serde_json depends on 1.0.66
         # once_cell v0.15.0 uses edition 2021.
-        run: cargo update -p serde --precise 1.0.156 && cargo update -p once_cell --precise 1.14.0
+        run: cargo update -p serde_json --precise 1.0.99 && cargo update -p serde --precise 1.0.156  && cargo update -p once_cell --precise 1.14.0
+
       - name: Test
         run: cargo test --features ${{ matrix.rust.features }}
       - name: Wipe