fix: Add a step to install nightly toolchain

.github/workflows/build.yml

@@ -9,6 +9,11 @@ jobs:
     steps:
       - name: Checkout latest
         uses: actions/checkout@master
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+            toolchain: nightly
+            override: true
       - name: Cargo build
         uses: actions-rs/cargo@v1
         with:

.github/workflows/publish.yml

@@ -11,6 +11,11 @@ jobs:
     steps:
       - name: Checkout latest master
         uses: actions/checkout@master
+      - name: Install nightly toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+            toolchain: nightly
+            override: true
       - name: Login to crates.io
         uses: actions-rs/cargo@v1
         with: