Add conditional steps to Bank Feeds SDK docs

Author: jbyrnecodat

docs/bank-feeds/bank-feeds-sdk.md

@@ -62,6 +62,13 @@ npm add @codat/sdk-bank-feeds-types
 yarn add @codat/sdk-bank-feeds-types
 ```
 
+**Conditional steps**
+
+- **If you're using TypeScript**, extend your type declarations with our types by installing the types package using npm install --save-dev @codat/sdk-bank-feeds-types. Otherwise, delete the type-related code in the snippets.
+- **If you're using content security policy (CSP) headers**, edit these headers:
+  - Allowlist Codat by adding `*.codat.io` to `default-src` (or each of `script-src`, `style-src`, `font-src`, `connect-src`, `img-src`).
+  - Add `unsafe-inline` to `style-src`. Do _not_ use a hash because this can change at any time without warning.
+
 Create a component which initializes the SDK:
 
 ```react