test(ci): update opt version

Author: Kinplemelon

.github/workflows/build_emqx_for_test.yaml

@@ -12,9 +12,10 @@ jobs:
     runs-on: ubuntu-latest
     env:
       EMQX_NAME: ${{ inputs.emqx-name }}
-      OTP_VSN: '25.3.2-2'
+      OTP_VSN: '26.2.5-3'
       ELIXIR_VSN: '1.15.7'
 
+
     steps:
       - name: checkout emqx code
         uses: actions/checkout@v3