misc: add maintenance notice

.github/workflows/ci.yml

@@ -10,21 +10,21 @@ on:
 jobs:
   lint_python:
     name: Lint Python Code
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - name: Check out Git repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install Linters
         run: make venv
       - name: Lint
         run: make lint
   push_to_pypi:
     name: Build (and publish, if applicable)
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     needs: lint_python
     steps:
       - name: Check out Git repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Export Repo URL

Readme.md

@@ -1,8 +1,16 @@
+<p align="center">
+    <a href="https://github.com/fossi-foundation/ciel"><img src="./volare_banner.svg" width="80%" alt="Volare development has moved to
+the FOSSi Foundation: Check out Ciel, the community-driven successor to Volare maintained under the FOSSi Foundation with support for sky130, gf180mcu and ihp-sg13g2. For ChipFoundry-specific PDK releases, check out github.com/chipfoundry/ciel-releases"></a>
+</p>
+
+<p align="center">This repository is preserved as-is for archival purposes.</p>
+
+---
+
 <h1 align="center">⛰️ Volare</h1>
 <p align="center">
     <a href="https://opensource.org/licenses/Apache-2.0"><img src="https://img.shields.io/badge/License-Apache%202.0-blue.svg" alt="License: Apache 2.0"/></a>
     <img src="https://github.com/efabless/volare/actions/workflows/ci.yml/badge.svg?branch=main" alt="CI Status" />
-    <a href="https://invite.skywater.tools"><img src="https://img.shields.io/badge/Community-Skywater%20PDK%20Slack-ff69b4?logo=slack" alt="Invite to the Skywater PDK Slack"/></a>
     <a href="https://github.com/psf/black"><img src="https://img.shields.io/badge/code%20style-black-000000.svg" alt="Code Style: Black"/></a>
 </p>