setup libs-api ACP process

Author: yaahc

.github/ISSUE_TEMPLATE/api-change-proposal.md

@@ -0,0 +1,31 @@
+---
+name: API Change Proposal
+about: Propose a new API change to the libs-api team
+title: "(My API Change Proposal)"
+labels: api-change-proposal, T-libs-api
+assignees: ""
+---
+
+# Proposal
+
+## Problem statement
+
+_Start with a concise description of the problem(s) this API change proposal is trying to solve._
+
+## Motivation, use-cases
+
+_Next add any motivating examples. Examples should ideally be real world examples or minimized versions of the real world example in scenarios where the motivating code is not open source._
+
+## Solution sketches
+
+_Please also sketch out one or more solutions to the problem. You don't have to have all the details worked out, but it should be enough to convey the idea._
+
+## Links and related work
+
+_Provide links to any internal thread(s), github issues, related work from other languages, or other things that are worth following up on._
+
+## What happens now?
+
+This issue is part of the libs-api-team [API change proposal process]. Once this issue is filed the libs-api team will review open proposals in its weekly triage meetings. You should receive feedback within a week or two.
+
+[API change proposal]: https://std-dev-guide.rust-lang.org/feature-lifecycle/api-change-proposal.html

triagebot.toml

@@ -0,0 +1,6 @@
+[major-change]
+second_label = "initial-comment-period"
+meeting_label = "I-nominated"
+# can be found by looking for the first number in URLs, e.g. https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler
+# zulip_stream =
+# zulip_ping = "T-libs-api"