Add Sakibul to the bors team

And also rename to team to just "bors", the "infra-" prefix is unnecessary.

Author: Kobzol

teams/infra-bors.toml renamed to teams/bors.toml

@@ -1,4 +1,4 @@
-name = "infra-bors"
+name = "bors"
 subteam-of = "infra"
 
 [people]
@@ -7,6 +7,7 @@ members = [
     "Mark-Simulacrum",
     "pietroalbini",
     "Kobzol",
+    "Sakib25800"
 ]
 alumni = []