Pin dependencies

tools/coder-cli/Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:latest
+FROM alpine:latest@sha256:4b7ce07002c69e8f3d704a9c5d6fd3053be500b7f1c69fc0d80990c2ad8dd412
 
 RUN apk add --no-cache curl sed
 RUN curl -fsSL https://coder.com/install.sh | sh

tools/terraform-shell/Dockerfile

@@ -1,2 +1,2 @@
-FROM docker.io/hashicorp/terraform:1.12.2
+FROM docker.io/hashicorp/terraform:1.12.2@sha256:f5ac787eee9d292b6a3b97d40f04019ce08189d356233fc73d5ec7ef8529cce2
 ENTRYPOINT []