[CI] Hugo serve to/from memory, as was the case before

(Otherwise you can, for example, break link checking because live-upload URLS are inserted by the server.)

package.json

@@ -28,7 +28,7 @@
     "_prettier:any": "npx prettier --ignore-path ''",
     "_rename-to-kebab-case": "find assets content static -name '*_*' ! -name '_*' -exec sh -c 'mv \"$1\" \"${1//_/-}\"' _ {} \\;",
     "_serve:hugo": "hugo server -DFE --minify",
-    "_serve:netlify": "netlify dev -c \"npm run _serve:hugo\"",
+    "_serve:netlify": "netlify dev -c \"npm run _serve:hugo -- --renderToMemory\"",
     "_sync": "./scripts/sync-submodules.pl",
     "all": "bash -c 'x=0; for c in \"$@\"; do npm run $c || x=$((x+1)); done; ((!x)) || (echo \"ERROR: some scripts failed!\" && exit 1)' -",
     "build:preview": "set -x && npm run _build -- --minify",
@@ -77,9 +77,9 @@
     "prefix:submodules": "npm run update:submodule",
     "schemas:update": "npm run update:submodule content-modules/opentelemetry-specification",
     "seq": "bash -c 'for cmd in \"$@\"; do npm run $cmd || exit 1; done' - ",
-    "serve:hugo": "npm run _serve:hugo",
+    "serve:hugo": "npm run _serve:hugo -- --renderToMemory",
     "serve:netlify": "npm run _serve:netlify",
-    "serve": "npm run serve:hugo",
+    "serve": "npm run serve:hugo --",
     "sync": "./scripts/sync-submodules.pl",
     "test-and-fix": "npm run seq -- check fix:dict fix:filenames",
     "test": "npm run check",