MSRV fixes

Author: sanket1729

.github/workflows/rust.yml

@@ -106,5 +106,8 @@ jobs:
           profile: minimal
           toolchain: ${{ matrix.rust }}
           override: true
+      - name: Pin deps for rust 1.48
+        if: matrix.rust == '1.48.0'
+        run: cargo update -p serde --precise 1.0.156 && cargo update -p serde_test --precise 1.0.156
       - name: Running cargo in release mode
         run: cargo test --features="global-context" --release

contrib/test.sh

@@ -6,6 +6,14 @@ FEATURES="hashes global-context lowmemory rand rand-std recovery serde"
 cargo --version
 rustc --version
 
+
+# Pin dependencies as required if we are using MSRV toolchain.
+if cargo --version | grep "1\.48"; then
+    # 1.0.157 uses syn 2.0 which requires edition 2021
+    cargo update -p serde --precise 1.0.156
+    cargo update -p serde_test --precise 1.0.156
+fi
+
 # Make all cargo invocations verbose
 export CARGO_TERM_VERBOSE=true