PSF landing page: Error 503 first byte timeout.

[MarkMangoba]

@dstufft & @ewdurbin reported Error 503 first byte timeout. https://www.python.org/psf-landing/.

[Mariatta]

I'm seeing: 504 Gateway Time-out. The server didn't respond in time.

[berkerpeksag]

Since we didn't get the same error again in the past three months and there were no commits in both python/pythondotorg and python/psf-salt repos that may cause the error, I'm going to mark this as a transient error.