fix: exclude release PRs from changelog entries

Release PRs (e.g. "v0.2.14 release") are tagged as the release commit
and must not appear in the next version's changelog.

Add isReleasePR() using a regexp that matches titles starting with a
semver version number (v0.x.y or 0.x.y). Apply the filter inside
getMergedPRsSince so these PRs are silently dropped before categorization.

Add TestIsReleasePR to verify the pattern matches release titles while
leaving normal PRs untouched.

Co-authored-by: weinong <4204090+weinong@users.noreply.github.com>

Author: Copilot

hack/changelog-generator/main.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"os"
 	"os/exec"
+	"regexp"
 	"sort"
 	"strings"
 	"time"
@@ -152,6 +153,16 @@ func decodePRStream(data []byte) ([]GitHubPR, error) {
 	return prs, nil
 }
 
+// releasePRTitle matches PR titles that represent a version release
+// (e.g. "v0.2.14 release") so they can be excluded from the changelog.
+var releasePRTitle = regexp.MustCompile(`(?i)^v?\d+\.\d+\.\d+`)
+
+// isReleasePR returns true when the PR title looks like a release commit
+// (e.g. "v0.2.14 release", "0.2.14 release").
+func isReleasePR(title string) bool {
+	return releasePRTitle.MatchString(strings.TrimSpace(title))
+}
+
 // getMergedPRsSince returns all merged PRs after the given time.
 func getMergedPRsSince(repo string, since time.Time) ([]GitHubPR, error) {
 	out, err := ghAPI(
@@ -168,7 +179,7 @@ func getMergedPRsSince(repo string, since time.Time) ([]GitHubPR, error) {
 	}
 	var prs []GitHubPR
 	for _, pr := range all {
-		if !pr.MergedAt.IsZero() && pr.MergedAt.After(since) {
+		if !pr.MergedAt.IsZero() && pr.MergedAt.After(since) && !isReleasePR(pr.Title) {
 			prs = append(prs, pr)
 		}
 	}

hack/changelog-generator/main_test.go

@@ -135,3 +135,27 @@ func TestGenerateChangelogEntry(t *testing.T) {
 		}
 	}
 }
+
+func TestIsReleasePR(t *testing.T) {
+	cases := []struct {
+		title    string
+		expected bool
+	}{
+		{"v0.2.14 release", true},
+		{"0.2.14 release", true},
+		{"v1.0.0", true},
+		{"v0.2.14", true},
+		// Regular PRs — must NOT be filtered
+		{"fix: nil pointer", false},
+		{"feat: add new login flow", false},
+		{"Bump Go to 1.24.11", false},
+		{"docs: update readme", false},
+		{"[Bug Fix] - PoP token crash", false},
+	}
+	for _, tc := range cases {
+		got := isReleasePR(tc.title)
+		if got != tc.expected {
+			t.Errorf("isReleasePR(%q) = %v; want %v", tc.title, got, tc.expected)
+		}
+	}
+}