chore(deps): update docker/setup-buildx-action action to v4

.gitea/workflows/build-only.yaml

@@ -21,7 +21,7 @@ jobs:
 
       # Set up Docker Buildx for building the image
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
         with:
           driver: remote
           endpoint: 'tcp://buildkitd:1234'

Dockerfile

@@ -54,7 +54,7 @@ RUN mkdir -p /rootfs/bin && \
 
 ################################################################################
 # App builder stage
-FROM golang:1.26.1-trixie@sha256:ab8c4944b04c6f97c2b5bffce471b7f3d55f2228badc55eae6cce87596d5710b AS app-builder
+FROM golang:1.25.8-trixie@sha256:bc16125656839ffe56154c675f7a9662bec2ef7d4060177239914e7c6d2fd8a8 AS app-builder
 
 COPY app/ /opt/app
 WORKDIR /opt/app