Update support matrix and ci to include 1.26

.github/workflows/ci.yaml

@@ -85,6 +85,7 @@ jobs:
         kind-image:
           - 'kindest/node:v1.28.0'
           - 'kindest/node:v1.27.3'
+          - 'kindest/node:v1.26.6'
     steps:
     - uses: actions/checkout@v3
       with:

.github/workflows/versions.yaml

@@ -5,17 +5,17 @@ on:
   schedule:
     - cron: '37 7 * * 1'
 env:
-  golang-version: '1.19'
+  golang-version: '1.20'
 jobs:
   versions:
     runs-on: ubuntu-latest
     strategy:
       matrix:
         branch:
-          - 'release-0.9'
           - 'release-0.10'
           - 'release-0.11'
           - 'release-0.12'
+          - 'release-0.13'
           - 'main'
     steps:
     - uses: actions/checkout@v3

README.md

@@ -45,7 +45,7 @@ The following Kubernetes versions are supported and work as we test against thes
 | [`release-0.10`](https://github.com/prometheus-operator/kube-prometheus/tree/release-0.10) | ✔               | ✔               | ✗               | ✗               | x               | x               | x               |
 | [`release-0.11`](https://github.com/prometheus-operator/kube-prometheus/tree/release-0.11) | ✗               | ✔               | ✔               | ✗               | x               | x               | x               |
 | [`release-0.12`](https://github.com/prometheus-operator/kube-prometheus/tree/release-0.12) | ✗               | ✗               | ✔               | ✔               | x               | x               | x               |
-| [`release-0.13`](https://github.com/prometheus-operator/kube-prometheus/tree/release-0.13) | ✗               | ✗               | ✗               | x               | x               | ✔               | ✔               |
+| [`release-0.13`](https://github.com/prometheus-operator/kube-prometheus/tree/release-0.13) | ✗               | ✗               | ✗               | x               | ✔               | ✔               | ✔               |
 | [`main`](https://github.com/prometheus-operator/kube-prometheus/tree/main)                 | ✗               | ✗               | ✗               | x               | x               | ✔               | ✔               |
 
 ## Quickstart