build: revert to Develocity Plugin v3 due to incompatibility

The Groovy project is currently incompatible with Develocity
Plugin version 4. To avoid breaking the joint build workflow,
we are reverting to version 3.

settings.gradle

diff --git a/settings.gradle b/settings.gradle
index dd7574d..51042f8 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -1,5 +1,5 @@
 plugins {
-    id 'com.gradle.develocity' version '4.0'
+    id 'com.gradle.develocity' version '3.19.2' // Do not upgrade to v4 until Groovy can build with it: https://lists.apache.org/thread/z3ohqxxmdm9p1y18j6mk1cpp6fvnz6k7
     id 'com.gradle.common-custom-user-data-gradle-plugin' version '2.2.1'
 }