message: feat(changelog): infer the base commit
diff: @@ -5,6 +5,12 @@ function gitShowFile(commit: string, path: string) {
  return execSync(`git show ${commit}:${path}`, { encoding: "utf-8" });
  }
  +function gitLatestTag() {
  + return execSync(`git describe --tags --abbrev=0`, {
  + encoding: "utf-8",
  + }).trim();
  +}
  +
  function mapInterfaceToMembers(interfaces: ts.InterfaceDeclaration[]) {
  const interfaceToMemberMap = new Map<string, string[]>();
  for (const decl of interfaces) {
  @@ -131,10 +137,7 @@ function writeAddedRemovedInline(added: Set<string>, removed: Set<string>) {
  const dom = "baselines/dom.generated.d.ts";
  async function main() {
  - const [base, head = "HEAD"] = process.argv.slice(2);
  - if (!base) {
  - throw new Error("This needs a commit identifier as a parameter");
  - }
  + const [base = gitLatestTag(), head = "HEAD"] = process.argv.slice(2);
  const previous = gitShowFile(base, dom);
  const current = gitShowFile(head, dom);
  const {
  