[ios, build] Fix bad changelog header and improve handling

Also, specifically require `execSync`.

platform/ios/CHANGELOG.md

@@ -22,7 +22,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * Added a new option to `MGLSymbolPlacement`, `MGLSymbolPlacementLineCenter`, that places the label relative to the center of the geometry. ([#12337](https://github.com/mapbox/mapbox-gl-native/pull/12337))
 * Added a `MGLShapeSourceOptionLineDistanceMetrics` property that enables or disables calculating line distance metrics.
 
-## User location
+### User location
 
 * Added an `MGLMapView.locationManager` property and `MGLLocationManager` protocol for tracking user location using a custom alternative to `CLLocationManager`. ([#12013](https://github.com/mapbox/mapbox-gl-native/pull/12013))
 * Fixed a crash that occurred when `MMELocationManager` was deallocated and the delegate was reporting updates. ([#12542](https://github.com/mapbox/mapbox-gl-native/pull/12542))

platform/ios/scripts/release-notes.js

@@ -1,7 +1,7 @@
 #!/usr/bin/env node
 
 const fs = require('fs');
-const child_process = require('child_process');
+const execSync = require('child_process').execSync;
 const ejs = require('ejs');
 const _ = require('lodash');
 const semver = require('semver');
@@ -11,12 +11,12 @@ const changelog = fs.readFileSync('platform/ios/CHANGELOG.md', 'utf8');
 /*
   Find current and immediately previous releases by parsing git tags.
 */
-let currentVersion = child_process.execSync('git describe --tags --match=ios-v*.*.* --abbrev=0')
+let currentVersion = execSync('git describe --tags --match=ios-v*.*.* --abbrev=0')
     .toString()
     .trim()
     .replace('ios-v', '');
 
-let gitTags = child_process.execSync('git tag --list ios-v*.*.*')
+let gitTags = execSync('git tag --list ios-v*.*.*')
     .toString()
     .split('\n')
     .map(function (tag) {
@@ -29,13 +29,13 @@ let previousVersion = semver.maxSatisfying(gitTags, "<" + currentVersion);
   Parse the raw changelog text and split it into individual releases.
 
   This regular expression:
-    - Matches lines starting with "## ".
+    - Matches lines starting with "## x.x.x".
     - Groups the version number.
     - Skips the (optional) release date.
     - Groups the changelog content.
-    - Ends when another "## " is found.
+    - Ends when another "## x.x.x" is found.
 */
-const regex = /^## (\d+\.\d+\.\d+).*?\n(.+?)(?=\n^## )/gms;
+const regex = /^## (\d+\.\d+\.\d+).*?\n(.+?)(?=\n^## \d+\.\d+\.\d+.*?\n)/gms;
 
 let releaseNotes = [];
 while (match = regex.exec(changelog)) {