endpoints: update Facebook endpoints

[MerleLiuKun]

After May 4th, 2021, Facebook graph api version 3.2 has been stop service. Need update to use link without version tag.

Refer: https://developers.facebook.com/docs/graph-api/changelog/version3.2

[gopherbot]

This PR (HEAD: 872c265) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/oauth2/+/351449 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

[gopherbot]

This PR (HEAD: 4399298) has been imported to Gerrit for code review.

Please visit https://go-review.googlesource.com/c/oauth2/+/351449 to see it.

Tip: You can toggle comments from me using the comments slash command (e.g. /comments off)
See the Wiki page for more info

[gopherbot]

Message from JBD (DO NOT USE):

Patch Set 7: Code-Review+1

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/351449.
After addressing review feedback, remember to publish your drafts!

[gopherbot]

Message from kun liu:

Patch Set 7:

(1 comment)

---

Please don’t reply on this GitHub thread. Visit golang.org/cl/351449.
After addressing review feedback, remember to publish your drafts!