feat(flagd): Update documentation for azblob sync type

Signed-off-by: vmai <[email protected]>

Author: VMaievskyi

chart/open-feature-operator/values.yaml

@@ -41,6 +41,7 @@ sidecarConfiguration:
   ## @param sidecarConfiguration.providerArgs Used to append arguments to the sidecar startup command. This value is a comma separated string of key values separated by '=', e.g. `key=value,key2=value2` results in the appending of `--sync-provider-args key=value --sync-provider-args key2=value2`.
   providerArgs: ""
   ## @param sidecarConfiguration.envVarPrefix Sets the prefix for all environment variables set in the injected sidecar.
+  ## Needs to be empty to support azblob sync type
   envVarPrefix: "FLAGD"
   ## @param sidecarConfiguration.defaultSyncProvider Sets the value of the `XXX_SYNC_PROVIDER` environment variable for the injected sidecar container. There are 4 valid sync providers: `kubernetes`, `grpc`, `file` and `http`.
   defaultSyncProvider: kubernetes

docs/feature_flag_source.md

@@ -83,6 +83,23 @@ sources:
     selector: 'source=database,app=weatherapp'  # flag filtering options
 ```
 
+### azblob
+
+Given below is an example configuration with provider type `azblob` and supported options,
+
+```yaml
+sources:
+  - source: azblob://my-bucket/test.json # my-bucket - container name
+    provider: azblob
+  envVarPrefix: "" # MUST be empty to prevent adding prefix to next env vars
+  envVars:
+    - name: AZURE_STORAGE_ACCOUNT
+      value: <account_name>
+    - name: AZURE_STORAGE_SAS_TOKEN
+      value: <SAS token>
+```
+Other type of credentials for Azure Blob Storage are supported, for details (see [AZ credentials config](https://pkg.go.dev/gocloud.dev/blob/azureblob#hdr-URLs))
+
 ## Sidecar configurations
 
 `FeatureFlagSource` provides configurations to the injected flagd sidecar.