Add input length cap and parenthesis depth limit to expression parser (…

…#13)

parseAtom recurses into parseExpression on each open parenthesis with no
depth bound, so a long run of '(' overflows the goroutine stack and
fatally crashes the process. Adds a depth counter on the parser struct
checked on each open paren, and a 1 MiB input length cap at the top of
Parse and ParseStrict. Both return ErrExpressionTooLarge.

Bump github.com/stretchr/testify to v1.11.1

Merge pull request #7 from git-pkgs/dependabot/github_actions/actions…

…/setup-go-6.3.0

Bump actions/setup-go from 6.2.0 to 6.3.0

Hello world