chore: remove readme synth.py config (#1415)

* chore(java): remove readme autosynth job config

README generation is now handled by owlbot

Source-Author: Jeff Ching <chingor@google.com>
Source-Date: Wed Sep 8 12:11:28 2021 -0700
Source-Repo: googleapis/synthtool
Source-Sha: df5093b950d4aafd49a4c7758d74c44485263ada
Source-Link: googleapis/synthtool@df5093b

* chore: remove readme synth.py config

Source-Author: Jeff Ching <chingor@google.com>
Source-Date: Wed Sep 8 13:23:41 2021 -0700
Source-Repo: googleapis/synthtool
Source-Sha: 2d31a9243781b282202b4f76dc7bbc8b45803196
Source-Link: googleapis/synthtool@2d31a92

* chore: add gcf-owl-bot to list of trusted contributors

Source-Author: Jeff Ching <chingor@google.com>
Source-Date: Wed Sep 8 13:42:12 2021 -0700
Source-Repo: googleapis/synthtool
Source-Sha: a6b97202771f89a4b76873d43ea9a07d7fc95f91
Source-Link: googleapis/synthtool@a6b9720

.github/trusted-contribution.yml

@@ -1,2 +1,3 @@
 trustedContributors:
-- renovate-bot
+- renovate-bot
+- gcf-owl-bot[bot]

synth.metadata

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-spanner.git",
-        "sha": "87b77a3be3fc9cb206e147dcce818b594b2c6b4b"
+        "sha": "0a311ad38558dbf91c863941165cce456cf3c14c"
       }
     },
     {
@@ -19,7 +19,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "17ee6e5c08f2eb47029beee4776ce990e56b3925"
+        "sha": "a6b97202771f89a4b76873d43ea9a07d7fc95f91"
       }
     }
   ],
@@ -58,7 +58,6 @@
     ".github/ISSUE_TEMPLATE/support_request.md",
     ".github/PULL_REQUEST_TEMPLATE.md",
     ".github/generated-files-bot.yml",
-    ".github/readme/synth.py",
     ".github/release-trigger.yml",
     ".github/snippet-bot.yml",
     ".github/trusted-contribution.yml",
@@ -70,7 +69,6 @@
     ".kokoro/common.cfg",
     ".kokoro/common.sh",
     ".kokoro/continuous/java8.cfg",
-    ".kokoro/continuous/readme.cfg",
     ".kokoro/dependencies.sh",
     ".kokoro/nightly/integration.cfg",
     ".kokoro/nightly/java11.cfg",