Revert "Disable riscv64gc"

This reverts commit 3ad356d.

Author: workingjubilee

.github/workflows/ci.yml

@@ -121,8 +121,7 @@ jobs:
           # for NaNs which makes it worth testing on despite that.
           - mips-unknown-linux-gnu
           - mips64-unknown-linux-gnuabi64
-          # TODO: reenable pending https://github.com/rust-lang/rust/issues/77866
-          # - riscv64gc-unknown-linux-gnu
+          - riscv64gc-unknown-linux-gnu
 
     steps:
       - uses: actions/checkout@v2