Run CIFuzz continuous integration on PRs. (#133)
Run CIFuzz continuous integration on PRs. (#133)

oss-fuzz provides a GitHub CI integration that would run the fuzzer on a
given pull request for a period of time. The minimum recommended time is
600 seconds, which is the value included in this commit.

See the following link for details:

  https://google.github.io/oss-fuzz/getting-started/continuous-integration/
libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl,libjxl/libjxl