Feat: Add startsWith to String builtins

[rorymalcolm]

• Adds startsWith to the String builtins
• Adds a test to ensure it works as intended

[stevenh]

Thanks @rorymalcolm

[rorymalcolm]

Thanks @rorymalcolm

Thanks for merging! Is there a release schedule for this project? I noticed there's been changes but no release since last year. Understand your job as a maintainer is difficult, if I can be of any help let me know!

[stevenh]

Good call out @rorymalcolm had just slipped my mind, actually really simple just need to create a tag and wait for the github action to run, so its like 10seconds of work which I've just done so v0.3.0 is now live