fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE310-APKTOOLS-1534688
- https://snyk.io/vuln/SNYK-ALPINE310-MUSL-458452
- https://snyk.io/vuln/SNYK-ALPINE310-MUSL-458452
- https://snyk.io/vuln/SNYK-ALPINE310-OPENSSL-1089244
- https://snyk.io/vuln/SNYK-ALPINE310-OPENSSL-587954

Dockerfile

@@ -5,7 +5,7 @@ WORKDIR /app
 
 RUN CGO_ENABLED=0 GOOS=linux go build -ldflags '-extldflags "-static"'
 
-FROM alpine:3.10.1
+FROM alpine:3.14
 
 RUN addgroup --gid 1000 app && \
     adduser --system --uid 1000 --ingroup app app