Don't use hash-based Docker image version

Author: JoshMock

.buildkite/Dockerfile

@@ -1,5 +1,5 @@
 ARG NODE_VERSION=${NODE_VERSION:-18}
-FROM node:latest@sha256:840dad0077213cadd2d734d542ae11cd0f648200be29504eb1b6e2c995d2b75a:$NODE_VERSION
+FROM node:$NODE_VERSION
 
 # Install required tools
 RUN apt-get clean -y && \

.buildkite/Dockerfile-make

@@ -1,5 +1,5 @@
 ARG NODE_JS_VERSION=${NODE_JS_VERSION:-18}
-FROM node:latest@sha256:840dad0077213cadd2d734d542ae11cd0f648200be29504eb1b6e2c995d2b75a:${NODE_JS_VERSION}
+FROM node:${NODE_JS_VERSION}
 
 ARG BUILDER_UID=1000
 ARG BUILDER_GID=1000