fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE318-OPENSSL-6032386
- https://snyk.io/vuln/SNYK-ALPINE318-OPENSSL-6032386
- https://snyk.io/vuln/SNYK-ALPINE318-BUSYBOX-7249236
- https://snyk.io/vuln/SNYK-ALPINE318-BUSYBOX-7249265
- https://snyk.io/vuln/SNYK-ALPINE318-BUSYBOX-7249419

Dockerfile

@@ -5,7 +5,7 @@ WORKDIR /app
 
 RUN CGO_ENABLED=0 GOOS=linux go build -ldflags '-extldflags "-static"'
 
-FROM alpine:3.18.3
+FROM alpine:3
 
 RUN addgroup --gid 1000 app && \
     adduser --system --uid 1000 --ingroup app app