Fix version bump script (#2054)

* Fix version bump script failure

It was trying to run `.replace` on a Buffer instead of a string.

* Correctly set Node version in Docker

Author: JoshMock

.ci/Dockerfile

@@ -1,4 +1,4 @@
-ARG NODE_JS_VERSION=18
+ARG NODE_JS_VERSION=${NODE_JS_VERSION:-18}
 FROM node:${NODE_JS_VERSION}
 
 ARG BUILDER_UID=1000

.ci/make.mjs

@@ -86,10 +86,10 @@ async function bump (args) {
     'utf8'
   )
 
-  const pipeline = await readFile(join(import.meta.url, '..', '.buildkite', 'pipeline.yml'))
+  const pipeline = await readFile(join(import.meta.url, '..', '.buildkite', 'pipeline.yml'), 'utf8')
   await writeFile(
     join(import.meta.url, '..', '.buildkite', 'pipeline.yml'),
-    pipeline.replace(/STACK_VERSION: [0-9]+[0-9\.]*[0-9](?:\-SNAPSHOT)?/, `STACK_VERSION: ${cleanVersion}-SNAPSHOT`), // eslint-disable-line
+    pipeline.replace(/STACK_VERSION: [0-9]+[0-9\.]*[0-9](?:\-SNAPSHOT)?/, `STACK_VERSION: ${cleanVersion}-SNAPSHOT`),
     'utf8'
   )
 }