Auto merge of #3020 - ehuss:highfive-triagebot2, r=JohnTitor

Migrate from highfive to triagebot

This migrates this repository from using the highfive bot to using triagebot (aka rustbot).

This is ready to merge now, feel free to merge to re-enable auto-assignment.

triagebot.toml

@@ -3,4 +3,23 @@ allow-unauthenticated = [
     "C-*", "O-*", "S-*"
 ]
 
+[autolabel."S-waiting-on-review"]
+new_pr = true
+
 [assign]
+contributing_url = "https://github.com/rust-lang/libc/blob/master/CONTRIBUTING.md"
+
+[assign.owners]
+"*" = ["@JohnTitor"]
+
+[mentions."src/unix/bsd/netbsdlike/openbsd"]
+message = "Some changes occurred in OpenBSD module"
+cc = ["@semarie"]
+
+[mentions."src/unix/bsd/netbsdlike/mod.rs"]
+message = "Some changes occurred in OpenBSD module"
+cc = ["@semarie"]
+
+[mentions."src/unix/solarish"]
+message = "Some changes occurred in solarish module"
+cc = ["@jclulow", "@pfmooney"]