Bump alpine from 3.15.0 to 3.15.1 (#731)

Bumps alpine from 3.15.0 to 3.15.1.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Dockerfile

@@ -15,7 +15,7 @@ RUN go get -u github.com/gobuffalo/packr/v2/packr2
 COPY . .
 RUN packr2 build -a -o polaris *.go
 
-FROM alpine:3.15.0
+FROM alpine:3.15.1
 WORKDIR /usr/local/bin
 RUN apk --no-cache add ca-certificates