Use the newer nightly to fix the build

Author: JohnTitor

.github/workflows/bors.yml

@@ -235,7 +235,7 @@ jobs:
       - uses: actions/checkout@v2
       - name: Setup Rust toolchain
         # FIXME: Pin nightly version to make semverver compilable.
-        run: TOOLCHAIN=nightly-2020-06-18 sh ./ci/install-rust.sh
+        run: TOOLCHAIN=nightly-2020-11-19 sh ./ci/install-rust.sh
       - name: Check breaking changes
         run: sh ci/semver.sh linux
 
@@ -252,7 +252,7 @@ jobs:
       - uses: actions/checkout@v2
       - name: Setup Rust toolchain
         # FIXME: Pin nightly version to make semverver compilable.
-        run: TOOLCHAIN=nightly-2020-06-18 sh ./ci/install-rust.sh
+        run: TOOLCHAIN=nightly-2020-11-19 sh ./ci/install-rust.sh
       - name: Check breaking changes
         run: sh ci/semver.sh macos