Put specific versions for Docker containers

This is done to remove potential bugs caused by a dependency change
Update the versions must be done manually and validated with automated tests

dom/Dockerfile

@@ -1,4 +1,4 @@
-FROM buildkite/puppeteer
+FROM buildkite/puppeteer:5.2.1
 
 ENV GIT_TERMINAL_PROMPT=0
 RUN apt-get update

go/exam/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1-alpine
+FROM golang:1.14.6-alpine3.12
 
 ENV GIT_TERMINAL_PROMPT=0
 RUN apk add --no-cache git

go/tests/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1-alpine
+FROM golang:1.14.6-alpine3.12
 
 ENV GIT_TERMINAL_PROMPT=0
 RUN apk add --no-cache git

js/tests/Dockerfile

@@ -1,4 +1,4 @@
-FROM node:14-alpine
+FROM node:14.7.0-alpine3.12
 
 ENV GIT_TERMINAL_PROMPT=0
 RUN apk add --no-cache git

sh/tests/Dockerfile

@@ -1,4 +1,4 @@
-FROM debian:stable-slim
+FROM debian:10.5-slim
 
 RUN apt-get update
 RUN apt-get -y install jq curl git