Upgrade to Unity 2020.3.15f

Packages/manifest.json

 {
   "dependencies": {
-    "com.unity.collab-proxy": "1.5.7",
+    "com.unity.collab-proxy": "1.7.1",
-    "com.unity.test-framework": "1.1.26",
+    "com.unity.test-framework": "1.1.27",
     "com.unity.textmeshpro": "3.0.6",
     "com.unity.toolchain.win-x86_64-linux-x86_64": "0.1.20-preview",
     "com.unity.ugui": "1.0.0",

Packages/packages-lock.json

       "url": "https://packages.unity.com"
     },
     "com.unity.collab-proxy": {
-      "version": "1.5.7",
+      "version": "1.7.1",
       "depth": 0,
       "source": "registry",
       "dependencies": {
       "url": "https://packages.unity.com"
     },
     "com.unity.test-framework": {
-      "version": "1.1.26",
+      "version": "1.1.27",
       "depth": 0,
       "source": "registry",
       "dependencies": {

ProjectSettings/ProjectVersion.txt

-m_EditorVersion: 2020.3.14f1
-m_EditorVersionWithRevision: 2020.3.14f1 (d0d1bb862f9d)
+m_EditorVersion: 2020.3.15f2
+m_EditorVersionWithRevision: 2020.3.15f2 (6cf78cb77498)