Update alpine Docker tag to v3.18.4

This MR contains the following updates:

Package	Type	Update	Change
alpine	final	patch	3.18.3 -> 3.18.4

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Dockerfile

@@ -13,7 +13,7 @@ RUN go mod download \
   && go build -v ./cmd/transmission-exporter
 
 # 2. stage
-FROM alpine:3.18.3
+FROM alpine:3.18.4
 COPY --from=build /app/transmission-exporter /usr/bin/transmission-exporter
 # COPY --chmod=755 .. requires Buildkit
 RUN chmod 755 /usr/bin/transmission-exporter \