fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE316-BUSYBOX-6913410
- https://snyk.io/vuln/SNYK-ALPINE316-BUSYBOX-6913410

Dockerfile

@@ -4,7 +4,7 @@ COPY . .
 RUN VERSION=$(git describe --tags --abbrev=0) && \
 CGO_ENABLED=0 go build -o bin/gitleaks -ldflags "-X="github.com/zricethezav/gitleaks/v8/cmd.Version=${VERSION}
 
-FROM alpine:3.16
+FROM alpine:3.19
 RUN adduser -D gitleaks && \
     apk add --no-cache bash git openssh-client
 COPY --from=build /go/src/github.com/zricethezav/gitleaks/bin/* /usr/bin/