Add new env variable for Splunk 10, remove docker-compose version, add quotes to versions as is recommended

Author: Ickerday

docker-compose.yml

@@ -1,18 +1,17 @@
-version: '3.6'
-
 services:
     splunk:
         image: "splunk/splunk:${SPLUNK_VERSION}"
         container_name: splunk
         environment:
             - SPLUNK_START_ARGS=--accept-license
+            - SPLUNK_GENERAL_TERMS=--accept-sgt-current-at-splunk-com
             - SPLUNK_HEC_TOKEN=11111111-1111-1111-1111-1111111111113
             - SPLUNK_PASSWORD=changed!
             - SPLUNK_APPS_URL=https://github.com/splunk/sdk-app-collection/releases/download/v1.1.0/sdkappcollection.tgz
         ports:
-            - 8000:8000
-            - 8088:8088
-            - 8089:8089
+            - "8000:8000"
+            - "8088:8088"
+            - "8089:8089"
         healthcheck:
             test: ['CMD', 'curl', '-f', 'http://localhost:8000']
             interval: 5s