add BUILD_SPECIFIC_GCLOUD_PROJECT

Author: Takashi Matsuo

.kokoro/python2.7/common.cfg

@@ -43,3 +43,10 @@ env_vars: {
     key: "RUN_TESTS_SESSION"
     value: "py-2.7"
 }
+
+# Declare build specific Cloud project. It still uses the common one,
+# but we'll update the value once we have more Cloud projects.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests"
+}

.kokoro/python3.6/common.cfg

@@ -43,3 +43,10 @@ env_vars: {
     key: "RUN_TESTS_SESSION"
     value: "py-3.6"
 }
+
+# Declare build specific Cloud project. It still uses the common one,
+# but we'll update the value once we have more Cloud projects.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests"
+}

.kokoro/python3.7/common.cfg

@@ -43,3 +43,10 @@ env_vars: {
     key: "RUN_TESTS_SESSION"
     value: "py-3.7"
 }
+
+# Declare build specific Cloud project.
+# Temporary setting my own project for testing the behavior on the PR.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "tmatsuo-test"
+}

.kokoro/python3.8/common.cfg

@@ -43,3 +43,10 @@ env_vars: {
     key: "RUN_TESTS_SESSION"
     value: "py-3.8"
 }
+
+# Declare build specific Cloud project. It still uses the common one,
+# but we'll update the value once we have more Cloud projects.
+env_vars: {
+    key: "BUILD_SPECIFIC_GCLOUD_PROJECT"
+    value: "python-docs-samples-tests"
+}