Add GitHub Action for publishing the extension CLI (#9542)

This PR adds a GitHub Action for publishing the extension CLI.

When the `extension-cli` tag is pushed, this Action will run, build the
`zed-extension` binary, and upload it to DigitalOcean for consumption.

This will allow us to consume the pre-built binary in the CI for the
extensions repo.

Release Notes:

- N/A

---------

Co-authored-by: Max <max@zed.dev>

script/lib/blob-store.sh

@@ -0,0 +1,33 @@
+function upload_to_blob_store_with_acl
+{
+    bucket_name="$1"
+    file_to_upload="$2"
+    blob_store_key="$3"
+    acl="$4"
+
+    date=$(date +"%a, %d %b %Y %T %z")
+    acl="x-amz-acl:public-read"
+    content_type="application/octet-stream"
+    storage_type="x-amz-storage-class:STANDARD"
+    string="PUT\n\n${content_type}\n${date}\n${acl}\n${storage_type}\n/${bucket_name}/${blob_store_key}"
+    signature=$(echo -en "${string}" | openssl sha1 -hmac "${DIGITALOCEAN_SPACES_SECRET_KEY}" -binary | base64)
+
+    curl --fail -vv -s -X PUT -T "$file_to_upload" \
+        -H "Host: ${bucket_name}.nyc3.digitaloceanspaces.com" \
+        -H "Date: $date" \
+        -H "Content-Type: $content_type" \
+        -H "$storage_type" \
+        -H "$acl" \
+        -H "Authorization: AWS ${DIGITALOCEAN_SPACES_ACCESS_KEY}:$signature" \
+        "https://${bucket_name}.nyc3.digitaloceanspaces.com/${blob_store_key}"
+}
+
+function upload_to_blob_store_public
+{
+    upload_to_blob_store_with_acl $1 $2 $3 "x-amz-acl:public-read"
+}
+
+function upload_to_blob_store
+{
+    upload_to_blob_store_with_acl $1 $2 $3 "x-amz-acl:private"
+}