Merge pull request #902 from muzarski/num-bigint-as-feature

Hide public usages of `num_bigint::BigInt` behind a feature flag

Author: Lorak-mmk

.github/workflows/rust.yml

@@ -40,6 +40,10 @@ jobs:
       run: cargo check --all-targets --manifest-path "scylla/Cargo.toml" --features "chrono"
     - name: Cargo check with time feature
       run: cargo check --all-targets --manifest-path "scylla/Cargo.toml" --features "time"
+    - name: Cargo check with num-bigint-03 feature
+      run: cargo check --all-targets --manifest-path "scylla/Cargo.toml" --features "num-bigint-03"
+    - name: Cargo check with num-bigint-04 feature
+      run: cargo check --all-targets --manifest-path "scylla/Cargo.toml" --features "num-bigint-04"
     - name: Build scylla-cql
       run: cargo build --verbose --all-targets --manifest-path "scylla-cql/Cargo.toml" --features "full-serialization"
     - name: Build