Bump OTP version in GitHub Actions (michalmuskala#153)

Author: kianmeng

.github/workflows/ci.yml

@@ -36,6 +36,8 @@ jobs:
             otp: 23
           - elixir: 1.13.x
             otp: 24
+          - elixir: 1.13.x
+            otp: 25
             warnings_as_errors: true
     env:
       MIX_ENV: test
@@ -70,7 +72,7 @@ jobs:
       - uses: actions/checkout@v2
       - uses: erlef/setup-beam@v1
         with:
-          otp-version: 24
+          otp-version: 25
           elixir-version: 1.13.x
       - name: Install Dependencies
         run: |