Update Flux version in all places

Dockerfile

@@ -9,7 +9,7 @@ ENV TAIKO_SKIP_CHROMIUM_DOWNLOAD=true
 ENV TAIKO_BROWSER_PATH=/usr/bin/chromium-browser
 ENV TAIKO_BROWSER_ARGS=--no-sandbox,--start-maximized,--disable-dev-shm-usage,--ignore-certificate-errors
 
-ADD https://github.com/fluxcd/flux2/releases/download/v0.22.0/flux_0.22.0_linux_amd64.tar.gz /tmp/
+ADD https://github.com/fluxcd/flux2/releases/download/v0.25.3/flux_0.25.3_linux_amd64.tar.gz /tmp/
 COPY ./requirements.txt /requirements.txt
 RUN \
   # Install kubectl from alpine edge until alpine 3.16 is released

docs/installation/install_stackspin.rst

@@ -22,7 +22,7 @@ Prerequisites
 -------------
 
 - ``kubectl`` (`installation instructions <https://kubernetes.io/docs/tasks/tools/#kubectl>`__)
-- ``flux version 0.22.0`` (`Download flux_0.22.0_linux_amd64.tar.gz <https://github.com/fluxcd/flux2/releases/download/v0.22.0/flux_0.22.0_linux_amd64.tar.gz>`_)
+- ``flux version 0.25.3`` (`Download flux_0.25.3_linux_amd64.tar.gz <https://github.com/fluxcd/flux2/releases/download/v0.25.3/flux_0.25.3_linux_amd64.tar.gz>`_)
 
 Configuration
 -------------

install/flux-version-check.sh

 #!/usr/bin/env bash
 
-if [ "$(flux --version)" != "flux version 0.22.0" ]; then
-  echo "The Stackspin installation only works with Flux version 0.22.0"
+if [ "$(flux --version)" != "flux version 0.25.3" ]; then
+  echo "The Stackspin installation only works with Flux version 0.25.3"
   exit 1
 fi