Add JAVA_26 to JRE enum

Add `JRE.JAVA_26` constant and introduce JDK 26-ea CI build

Closes #4642

Author: sormuras

.github/workflows/cross-version.yml

@@ -24,6 +24,8 @@ jobs:
         jdk:
         - version: 25
           type: ea
+        - version: 26
+          type: ea
     name: "OpenJDK ${{ matrix.jdk.version }} (${{ matrix.jdk.release || matrix.jdk.type }})"
     runs-on: ubuntu-latest
     steps:

documentation/src/docs/asciidoc/release-notes/release-notes-6.0.0-M1.adoc

@@ -129,6 +129,7 @@ repository on GitHub.
 * Kotlin's `suspend` modifier may now be applied to test and lifecycle methods.
 * The `Arguments` interface for parameterized tests is now officially a
   `@FunctionalInterface`.
+* `JAVA_26` has been added to the `JRE` enum for use with JRE-based execution conditions.
 
 
 [[release-notes-6.0.0-M1-junit-vintage]]

gradle/base/code-generator-model/src/main/resources/jre.yaml

@@ -30,3 +30,5 @@
   since: '5.11'
 - version: 25
   since: '5.11.4'
+- version: 26
+  since: '6.0.0'