Remove 2018.3 from the CI mix.

.yamato/upm-ci.yml

@@ -27,8 +27,6 @@ upmci_platforms:
     flavor: b1.large
 
 editor_versions:
-  - version: "2018.3"
-    display_name: "2018.3"
   - version: "2018.4"
     display_name: "2018.4"
   - version: "2019.2"
@@ -92,11 +90,7 @@ validate_package_{{platform.name}}_{{editor.display_name}}:
     type: {{platform.type}}
     flavor: {{platform.flavor}}
   commands:
-  {% if editor.version == "2018.3" %}
-    - npm install [email protected] --registry https://artifactory.prd.cds.internal.unity3d.com/artifactory/api/npm/upm-npm -g
-  {% else %}
     - npm install upm-ci-utils@stable --registry https://artifactory.prd.cds.internal.unity3d.com/artifactory/api/npm/upm-npm -g
-  {% endif %}
     - upm-ci package pack --package-path src/
     - upm-ci package test --package-path src/ --unity-version {{ editor.version }}
   artifacts: