fix: use right matrix keyword

Author: brauliomartinezlm

.github/workflows/build.yml

@@ -26,9 +26,9 @@ jobs:
           - openssl_2_2
           - openssl_2_1
         exclude:
-          - ruby: '2.4.10'
+          - ruby-version: '2.4.10'
             gemfile: openssl_3_0
-          - ruby: '2.5.8'
+          - ruby-version: '2.5.8'
             gemfile: openssl_3_0
     env:
       BUNDLE_GEMFILE: gemfiles/${{ matrix.gemfile }}.gemfile