CI: Add OTP 26.0-rc1 to the test matrix

But disable dialyzer in 26, as it complains verbosely without reason

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        otp: ['20.0', '21.3', '24.3', '25']
+        otp: ['20.0', '21.3', '24.3', '25', '26.0-rc1']
     runs-on: ubuntu-20.04
     services:
       redis:
@@ -149,6 +149,7 @@ jobs:
     - run: make options
     - run: make xref
     - run: make dialyzer
+      if: matrix.otp != '26.0-rc1'
 
     - name: Check Production Release
       run: |