test: add tests for Version.isMajorVersion (#1672)

Part of #1670.

Adding the test before fixing behavior of this method.

Author: krzema12

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

@@ -0,0 +1,23 @@
+package io.github.typesafegithub.workflows.shared.internal.model
+
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+
+class VersionTest :
+    FunSpec({
+        context("isMajorVersion") {
+            listOf(
+                Pair("v1.2.3", false),
+                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),
+            ).forEach { (version, isMajor) ->
+                test("isMajorVersion works correctly for $version") {
+                    Version(version).isMajorVersion() shouldBe isMajor
+                }
+            }
+        }
+    })