chore: add autogenerated api-report files to .gitignore (#2484)

When `yarn api-report` is ran, these files are automatically generated.
Since these are not tracked by git, they should be added to the
`.gitignore`.

Author: dlarocque

.gitignore

@@ -6,6 +6,8 @@
 /docs/
 /out/
 /build/
+temp/
+types/tsdoc-metadata.json
 system-test/secrets.js
 system-test/*key.json
 *.lock