chore(deps): update dependency ubuntu to v26

Author: mailerlite-renovate[bot]

.github/workflows/main.yml

@@ -5,7 +5,7 @@ on: push
 jobs:
   test:
     name: Python ${{ matrix.python-version }} tests
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       matrix:
         python-version: ["3.10", "3.11", "3.12", "3.13"]

.github/workflows/publish.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   build-n-publish:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10
       - name: Install uv