ci: Fix invalid yaml

[mydea]

It seems to not like double quotes.

See e.g. https://github.com/getsentry/sentry-javascript/actions/runs/4072470708

The workflow is not valid. .github/workflows/gitflow-sync-master.yml (Line: 16, Col: 9): Unexpected symbol: '"meta'. Located at position 89 within expression: github.event.pull_request.merged == true
&& startsWith(github.event.pull_request.title, "meta(changelog):")
 .github/workflows/gitflow-sync-master.yml (Line: 57, Col: 9): Unexpected symbol: '"meta'. Located at position 90 within expression: github.event.pull_request.merged == false
|| startsWith(github.event.pull_request.title, "meta(changelog):") == false

Note: This also fixes an incorrect check which meant we weren't running CI for all prs.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.91 KB (+0.19% 🔺)
@sentry/browser - ES5 CDN Bundle (minified)	61.72 KB (+0.24% 🔺)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.59 KB (+0.26% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	55.02 KB (+0.26% 🔺)
@sentry/browser - Webpack (gzipped + minified)	20.32 KB (+0.14% 🔺)
@sentry/browser - Webpack (minified)	66.48 KB (+0.17% 🔺)
@sentry/react - Webpack (gzipped + minified)	20.35 KB (+0.16% 🔺)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.64 KB (+0.08% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.82 KB (+0.1% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	25.12 KB (+0.17% 🔺)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	43.85 KB (+0.1% 🔺)
@sentry/replay - Webpack (gzipped + minified)	38.76 KB (+0.12% 🔺)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	61.48 KB (+0.12% 🔺)