alpine: demote from Tier 1 to Tier 2

The alpine image is quite different from other ones.
We have to admit that it is not as stable as other ones.

Signed-off-by: Akihiro Suda <[email protected]>

Author: AkihiroSuda

examples/README.md

@@ -4,14 +4,16 @@ To open a shell, run `limactl shell fedora bash` or `LIMA_INSTANCE=fedora lima b
 
 - - -
 
-⭐ = ["Tier 1"](#tier-1)
+⭐ = ["Tier 1"](#tier)
+
+☆ = ["Tier 2"](#tier)
 
 Default: [`default`](./default.yaml) (⭐Ubuntu, with containerd/nerdctl)
 
 Distro:
 - [`almalinux-8`](./almalinux-8.yaml): AlmaLinux 8
 - [`almalinux-9`](./almalinux-9.yaml), `almalinux.yaml`: AlmaLinux 9
-- [`alpine`](./alpine.yaml): ⭐Alpine Linux
+- [`alpine`](./alpine.yaml): ☆Alpine Linux
 - [`archlinux`](./archlinux.yaml): ⭐Arch Linux
 - [`centos-stream-8`](./centos-stream-8.yaml): CentOS Stream 8
 - [`centos-stream-9`](./centos-stream-9.yaml), `centos-stream.yaml`: CentOS Stream 9
@@ -67,8 +69,9 @@ Lost+found:
   [`oraclelinux-9`](./oraclelinux-9.yaml), and [`rocky-9`](./rocky-9.yaml) in Lima v0.13.0.
 - ~`nomad`~: Removed in Lima v0.17.1, as Nomad is [no longer free software](https://github.com/hashicorp/nomad/commit/b3e30b1dfa185d9437a25830522da47b91f78816)
 
-## Tier 1
+## Tier
 
-The "Tier 1" yamls (marked with ⭐) are regularly tested on the CI.
+- "Tier 1" (marked with ⭐): Good stability. Regularly tested on the CI.
+- "Tier 2" (marked with ☆): Moderate stability. Regularly tested on the CI.
 
 Other yamls are tested only occasionally and manually.