INTER-2051: Add SDK version support and EOL table to README

[kevinmia]

This PR addresses concerns raised in INTER-2051. This is the first PR for a FE SDK as a part of a thread of PRs that adds this table to the SDK README.

Adds a "Version support" section to the README with a single table showing which SDK major versions map to which JS Agent version, their current status, and end-of-support info.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟢	Statements	96.79%	151/156
🟢	Branches	95.51%	85/89
🟢	Functions	97.78%	44/45
🟢	Lines	97.33%	146/150

Test suite run success

41 tests passing in 15 suites.

Report generated by 🧪jest coverage report action from 055b72e

Show full coverage report

St	File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
🟢	All files	96.79	95.5	97.77	97.33
🟢	src	100	100	100	100
🟢	detect-env.ts	100	100	100	100
🟢	env.types.ts	100	100	100	100
🟢	...nt-context.ts	100	100	100	100
🟢	ssr.ts	100	100	100	100
🟢	...sitor-data.ts	100	100	100	100
🟢	src/components	100	100	100	100
🟢	...-provider.tsx	100	100	100	100
🟢	...vironment.tsx	100	100	100	100
🟢	src/utils	88.09	87.5	92.3	90
🟢	...is-defined.ts	100	100	100	100
🟢	...-cache-key.ts	80.76	83.33	85.71	84	5,10,43,52
🟢	to-error.ts	100	100	100	100
🟢	...mise-store.ts	100	100	100	100

[github-actions]

⚠️ This PR doesn't contain any changesets. If there are user-facing changes, don't forget to run:

pnpm exec changeset

to create a changeset.