fix: disable go cache in setup-go and fix ethereumjs Dockerfile casing

setup-go v6 defaults to caching via go.mod which doesn't exist in the
repo root. Also fix FROM...as -> FROM...AS casing lint warning.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: barnabasbusa

.github/actions/install-deps/action.yml

@@ -31,3 +31,4 @@ runs:
     if: contains(inputs.repository, 'prysm')
     with:
       go-version: '1.23.0'
+      cache: false

ethereumjs/Dockerfile

@@ -1,4 +1,4 @@
-FROM node:18-alpine as build
+FROM node:18-alpine AS build
 RUN apk update && apk add --no-cache bash git g++ make python3 && rm -rf /var/cache/apk/*
 WORKDIR /usr/app