update changelog & readme (missed documenting build step)

CHANGELOG.md

+## 0.8.4
+
+- Fixed casing of `AgreementResponse.agreement` to remove uppercase `A`
+- GraphQL peer dependency minimum compatible version downgraded to `14.5.8`. (Incompatibilities were between GraphQL & GraphiQL, not this lib.)
+
 ## 0.8.3
 
 - Added `classifiedAs` to `Organization`

README.md

@@ -107,7 +107,8 @@ We usually suggest that you do *not* enforce an http/https protocol scheme, to a
 
 ### Initialising for development
 
-- Run `yarn` from the top level folder of this repository to install and wire up all dependencies.
+1. Run `yarn` from the top level folder of this repository to install and wire up all dependencies.
+2. Run `npm run build` to compile the schema files.
 
 ### Available commands