Fix hadolint issues

Dockerfile

@@ -19,17 +19,17 @@
 ############################
 # STEP 1 build cosmovisor
 ############################
-FROM golang:alpine AS builder
+FROM golang:alpine3.15 AS builder
 
 # git is required for fetching the dependencies.
-RUN apk update && apk add --no-cache git
-
-RUN go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@v1.0.0
+RUN apk --no-cache add \
+  git=2.34.2-r0 && \
+  go install github.com/cosmos/cosmos-sdk/cosmovisor/cmd/cosmovisor@v1.0.0
 
 ############################
 # STEP 2 build node image
 ############################
-FROM alpine:latest
+FROM alpine:3.15
 
 COPY --from=builder /go/bin/cosmovisor /usr/bin/
 

integration_tests/deploy/Dockerfile

@@ -17,11 +17,11 @@
 ################################################################################
 FROM jrei/systemd-ubuntu:20.04
 
-RUN apt-get update && apt-get install -y \
-        sudo \
-        curl \
-        netcat \
-        iproute2 \
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        sudo=1.8.31-1ubuntu1.2 \
+        curl=7.68.0-1ubuntu2.10 \
+        netcat=1.206-1ubuntu1 \
+        iproute2=5.5.0-1ubuntu1 \
     && rm -rf /var/lib/apt/lists/*
 
 # test user