ci: add codespell to Fedora base image

.gitlab/ci/docker/fedora34/install_deps.sh

diff --git a/.gitlab/ci/docker/fedora34/install_deps.sh b/.gitlab/ci/docker/fedora34/install_deps.sh
index 4123d87..091bd64 100755
--- a/.gitlab/ci/docker/fedora34/install_deps.sh
+++ b/.gitlab/ci/docker/fedora34/install_deps.sh
@@ -23,6 +23,10 @@
     qt5-qttools-devel \
     qt6-qttools-devel
 
+# Install lint tools.
+dnf install --setopt=install_weak_deps=False -y \
+    codespell
+
 # Tools needed for the test suite.
 dnf install --setopt=install_weak_deps=False -y \
     findutils \