[SPARK-26317][BUILD] Upgrade SBT to 0.13.18

## What changes were proposed in this pull request?

SBT 0.13.14 ~ 1.1.1 has a bug on accessing `java.util.Base64.getDecoder` with JDK9+. It's fixed at 1.1.2 and backported to [0.13.18 (released on Nov 28th)](https://github.com/sbt/sbt/releases/tag/v0.13.18). This PR aims to update SBT.

## How was this patch tested?

Pass the Jenkins with the building and existing tests.

Closes apache#23270 from dongjoon-hyun/SPARK-26317.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>

project/build.properties

@@ -14,4 +14,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-sbt.version=0.13.17
+sbt.version=0.13.18