direct install fixed and updated latest pokemon go version, but if you want to keep the game without certificate revoked again.

Below step is what you gonna do!!

Download DNSCloak from AppStore store.
And check the video below.

'DNSCloak' (The free DNS app for iOS), follow the video tutorial: https://www.youtube.com/watch?v=H9hy-OrRMp8

ocsp.int-x3.letsencrypt.org
ocsp.apple.com
world-gen.g.aaplimg.com
mesu.apple.com
gdmf.apple.com
www.gdmf.apple.com
ppq.apple.com
iadsdk.apple.com
googleads.g.doubleclick.net
googletagservices.com
stats.g.doubleclick.net
adclick.g.douclick.net

Make sure the VPN option is always enabled in your settings, to validate a new certificate quickly disable VPN every time otherwise it won't let you sign the certificate, after the verification re-enable it.

P/S certificate might revoked, please do the step as fast as before you regret.