build(java): readme.sh should be executable (#300)

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Source-Link: googleapis/synthtool@0762e8e

Author: yoshi-automation

.kokoro/readme.sh

@@ -4,7 +4,7 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-speech.git",
-        "sha": "f7eaf01bccc5a2ce9426658931146c8adbe470a3"
+        "sha": "9e196b2f6d843f71d4e68da49f4dd2961b8a1578"
       }
     },
     {
@@ -27,7 +27,7 @@
       "git": {
         "name": "synthtool",
         "remote": "https://github.com/googleapis/synthtool.git",
-        "sha": "8a7a3021fe97aa0a3641db642fe2b767f1c8110f"
+        "sha": "0762e8ee2ec21cdfc4d82020b985a104feb0453b"
       }
     }
   ],