dev container: explicitly specify required platform

.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:rolling
+FROM --platform=linux/amd64 ubuntu:rolling
 
 ARG USER
 

.devcontainer/devcontainer.json

@@ -8,7 +8,8 @@
     "runArgs": [
         "--cap-add=SYS_PTRACE",
         "--security-opt",
-        "seccomp=unconfined"
+        "seccomp=unconfined",
+        "--platform", "linux/amd64"
     ],
     "updateRemoteUserUID": true,
     "remoteUser": "${localEnv:USER}",
@@ -23,6 +24,7 @@
                 "slevesque.shader"
             ],
             "settings": {
+                "extensions.verifySignature": false,
                 "terminal.integrated.defaultProfile.linux": "bash",
                 "terminal.integrated.profiles.linux": {
                     "bash": {