fix(shared): adjust how major version is inferred (#1671)

Fixes #1670.

Author: krzema12

shared-internal/src/main/kotlin/io/github/typesafegithub/workflows/shared/internal/model/Version.kt

@@ -25,7 +25,7 @@ data class Version(
 
     override fun toString(): String = version
 
-    fun isMajorVersion(): Boolean = version.contains(".").not()
+    fun isMajorVersion(): Boolean = version.removePrefix("v").removePrefix("V").toIntOrNull() != null
 
     suspend fun getReleaseDate() = dateProvider()
 }

shared-internal/src/test/kotlin/io/github/typesafegithub/workflows/shared/internal/model/VersionTest.kt

@@ -11,9 +11,8 @@ class VersionTest :
                 Pair("v1.2", false),
                 Pair("v3", true),
                 Pair("V3", true),
-                // Incorrect behavior, will be fixed in https://github.com/typesafegithub/github-workflows-kt/issues/1670
-                Pair("v3-prerelease", true),
-                Pair("beta-v3", true),
+                Pair("v3-prerelease", false),
+                Pair("beta-v3", false),
             ).forEach { (version, isMajor) ->
                 test("isMajorVersion works correctly for $version") {
                     Version(version).isMajorVersion() shouldBe isMajor