Bump proj4 from 2.6.2 to 2.6.3

Bumps [proj4](https://github.com/proj4js/proj4js) from 2.6.2 to 2.6.3.
- [Release notes](https://github.com/proj4js/proj4js/releases)
- [Changelog](https://github.com/proj4js/proj4js/blob/master/changelog.md)
- [Commits](https://github.com/proj4js/proj4js/compare/2.6.2...2.6.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -89,7 +89,7 @@
     "mocha": "8.2.1",
     "pixelmatch": "^5.1.0",
     "pngjs": "^6.0.0",
-    "proj4": "2.6.2",
+    "proj4": "2.6.3",
     "puppeteer": "5.5.0",
     "rollup": "^2.1.0",
     "rollup-plugin-babel": "^4.3.3",