chore: add devcontainer.json (#2545)

* chore: add devcontainer.json

* Set sockPort: location

.devcontainer/devcontainer.json

@@ -0,0 +1,14 @@
+{
+  "name": "KaTeX Codespaces",
+  "image": "mcr.microsoft.com/vscode/devcontainers/javascript-node:14",
+  "extensions": [
+    "dbaeumer.vscode-eslint",
+    "flowtype.flow-for-vscode",
+    "stylelint.vscode-stylelint",
+    "arcanis.vscode-zipfs"
+  ],
+  "settings": { 
+    "terminal.integrated.shell.linux": "/bin/bash"
+  },
+  "postCreateCommand": "git submodule update --init --recursive && CI=true yarn install"
+}

.gitpod.yml

@@ -1,6 +1,6 @@
 tasks:
   - init: yarn install
-    command: yarn start --sockPort 443
+    command: yarn start
   - openMode: split-right
     command: echo "Run 'yarn test' to run tests."
 

webpack.dev.js

@@ -19,6 +19,7 @@ katexConfig.devServer = {
     disableHostCheck: true,
     host: '0.0.0.0',
     port: PORT,
+    sockPort: 'location',
     stats: {
         colors: true,
     },