Merge pull request #370 from kzys/go115

Upgrade Go from 1.13 to 1.15

Author: Kazuyoshi Kato

.buildkite/pipeline.yml

@@ -11,7 +11,7 @@
 # express or implied. See the License for the specific language governing
 # permissions and limitations under the License.
 env:
-  PATH: "/usr/lib/go-1.13/bin:/usr/bin"
+  PATH: "/usr/lib/go-1.15/bin:/usr/bin"
   FC_TEST_DATA_PATH: "/tmp/buildkite_build_${BUILDKITE_BUILD_NUMBER}_testdata"
 
 steps:
@@ -127,6 +127,10 @@ steps:
       queue: "${BUILDKITE_AGENT_META_DATA_QUEUE:-default}"
       distro: "${BUILDKITE_AGENT_META_DATA_DISTRO}"
       hostname: "${BUILDKITE_AGENT_META_DATA_HOSTNAME}"
+    # Firecracker's main branch wouldn't work with Go SDK currently due to ht_enabled change.
+    # https://github.com/firecracker-microvm/firecracker/pull/2876
+    soft_fail:
+      - exit_status: 2
 
   - label: 'go mod tidy'
     commands: