chore: update migration notes for 1.37.0

Author: mefellows

website/docs/docs/on-premises/environment-variables.md

@@ -531,7 +531,7 @@ The secret used to encrypt the rack.session cookie.
 To generate an appropriate value, run the following on Linux/Mac:
 
 ```
-env LC_CTYPE=C tr -dc '_A-Z-a-z-0-9!#$%&*+-\\.^_|~' < /dev/urandom | fold -w 32 | head -n 1
+LC_ALL=C tr -dc '_A-Z-a-z-0-9!#$%&*+-\\.^_|~' < /dev/urandom | fold -w 64 | head -n 1
 ```
 
 **Required:** true<br/>

website/docs/docs/on-premises/releases/1.37.0.md

@@ -55,6 +55,7 @@ The following updates from the [Pact Broker](https://github.com/pact-foundation/
 - Explicitly ordered label lists by name  
   [commit](https://github.com/pact-foundation/pact_broker/commit/d25746c1)
 
+
 ## Migration notes
 
-No migration steps are required for this release.
+1. `PACTFLOW_COOKIE_SECRET` must now be at least 64 characters. [More info](/docs/on-premises/environment-variables#pactflow_cookie_secret).