chore: bump base image to bookworm and refresh action versions

.github/workflows/docker-publish.yml

@@ -55,7 +55,7 @@ jobs:
 
       - name: Build and push Docker image
         id: build-and-push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64,linux/arm/v7

.github/workflows/test-build.yml

@@ -17,7 +17,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Test build AMD64
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64
@@ -27,7 +27,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - name: Test build ARM64
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/arm64
@@ -37,7 +37,7 @@ jobs:
           cache-to: type=gha,mode=max
 
       - name: Test build ARM32
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/arm/v7

Dockerfile

@@ -1,4 +1,4 @@
-FROM debian:bullseye-slim
+FROM debian:bookworm-slim
 
 # Environment variables with defaults
 ENV TZ=Etc/UTC

README.md

@@ -151,7 +151,7 @@ This is a community project maintained on a volunteer basis.
 
 ## Version Information
 
-- **Base Image**: Debian Bullseye Slim
+- **Base Image**: Debian Bookworm Slim
 - **NUT Version**: Latest available from Debian repositories
 - **Architectures**: ARM32, ARM64, AMD64
 - **Update Schedule**: Automated monthly builds