ci: upgrade Fedora 40 to Fedora 41 in GitLab CI job for Fedora

Fedora 41 was released more than a month ago, so let's try to
use that.

.gitlab-ci.yml

@@ -39,9 +39,9 @@ docker_image_fedora:
     - docker:27-dind
   script:
     - cd ci/
-    - docker build -t $CI_REGISTRY/striezel/webp-viewer/fedora:40 . -f Dockerfile_fedora
+    - docker build -t $CI_REGISTRY/striezel/webp-viewer/fedora:41 . -f Dockerfile_fedora
     - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
-    - docker push $CI_REGISTRY/striezel/webp-viewer/fedora:40
+    - docker push $CI_REGISTRY/striezel/webp-viewer/fedora:41
     - docker logout $CI_REGISTRY
   # Only build new image when the Dockerfile or the GitLab CI configuration
   # changes.
@@ -51,7 +51,7 @@ docker_image_fedora:
       - .gitlab-ci.yml
 
 fedora:
-  image: registry.gitlab.com/striezel/webp-viewer/fedora:40
+  image: registry.gitlab.com/striezel/webp-viewer/fedora:41
   stage: test
   before_script:
     - yum update -y

ci/Dockerfile_fedora

@@ -1,5 +1,5 @@
 # This Dockerfile builds the image used during the fedora build job on GitLab.
-FROM fedora:40
+FROM fedora:41
 LABEL maintainer="Dirk Stolle <[email protected]>"
 # Always update any existing packages first.
 RUN yum update -y