Pin rayon-core in CI for MSRV compatibility. (#1504)

* Pin rayon-core in CI for MSRV compatibility.

* Pin rayon too.

* Remove windows-2019 from CI, as it is no longer supported.

* Update rayon before rayon-core.

Author: sunfishcode

.github/workflows/main.yml

@@ -60,6 +60,8 @@ jobs:
         cargo update --package=parking_lot --precise=0.12.3
         cargo update --package=parking_lot_core --precise=0.9.10
         cargo update --package=lock_api --precise=0.4.12
+        cargo update --package=rayon --precise=1.10.0
+        cargo update --package=rayon-core --precise=1.12.1
 
     - run: >
         rustup target add
@@ -250,7 +252,7 @@ jobs:
       RUSTFLAGS: --cfg rustix_use_experimental_features
     strategy:
       matrix:
-        build: [ubuntu, ubuntu-22.04, i686-linux, aarch64-linux, powerpc-linux, powerpc64le-linux, riscv64-linux, s390x-linux, arm-linux, ubuntu-stable, i686-linux-stable, aarch64-linux-stable, riscv64-linux-stable, s390x-linux-stable, powerpc-linux-stable, powerpc64le-linux-stable, arm-linux-stable, ubuntu-1.63, i686-linux-1.63, aarch64-linux-1.63, riscv64-linux-1.63, s390x-linux-1.63, powerpc64le-linux, powerpc64le-linux-1.63, arm-linux-1.63, macos-latest, macos-13, windows, windows-2019, musl]
+        build: [ubuntu, ubuntu-22.04, i686-linux, aarch64-linux, powerpc-linux, powerpc64le-linux, riscv64-linux, s390x-linux, arm-linux, ubuntu-stable, i686-linux-stable, aarch64-linux-stable, riscv64-linux-stable, s390x-linux-stable, powerpc-linux-stable, powerpc64le-linux-stable, arm-linux-stable, ubuntu-1.63, i686-linux-1.63, aarch64-linux-1.63, riscv64-linux-1.63, s390x-linux-1.63, powerpc64le-linux, powerpc64le-linux-1.63, arm-linux-1.63, macos-latest, macos-13, windows, musl]
         include:
           - build: ubuntu
             os: ubuntu-latest
@@ -456,9 +458,6 @@ jobs:
           - build: windows
             os: windows-latest
             rust: nightly-2025-06-23
-          - build: windows-2019
-            os: windows-2019
-            rust: nightly-2025-06-23
           - build: musl
             os: ubuntu-latest
             rust: stable
@@ -543,6 +542,8 @@ jobs:
         cargo update --package=parking_lot --precise=0.12.3
         cargo update --package=parking_lot_core --precise=0.9.10
         cargo update --package=lock_api --precise=0.4.12
+        cargo update --package=rayon --precise=1.10.0
+        cargo update --package=rayon-core --precise=1.12.1
 
     - run: |
         cargo test --verbose --features=all-apis --release --workspace -- --nocapture