Use Bintray API key rather than password in CI

Update CI scripts to use the Bintray API key rather than the password
when making curl calls.

Closes gh-15015

ci/scripts/promote.sh

@@ -64,7 +64,7 @@ if [[ $RELEASE_TYPE = "RELEASE" ]]; then
 	else
 		curl \
 			-s \
-			-u ${BINTRAY_USERNAME}:${BINTRAY_PASSWORD} \
+			-u ${BINTRAY_USERNAME}:${BINTRAY_API_KEY} \
 			-H "Content-Type: application/json" \
 			-d '[ { "name": "gradle-plugin", "values": ["org.springframework.boot:org.springframework.boot:spring-boot-gradle-plugin"] } ]' \
 			-X POST \
@@ -74,4 +74,4 @@ fi
 
 
 echo "Promotion complete"
-echo $version > version/version
+echo $version > version/version

ci/scripts/sync-to-maven-central.sh

@@ -11,9 +11,9 @@ echo "Syncing ${buildName}/${buildNumber} to Maven Central"
 			-s \
 			--connect-timeout 240 \
 			--max-time 2700 \
-			-u ${BINTRAY_USERNAME}:${BINTRAY_PASSWORD} \
+			-u ${BINTRAY_USERNAME}:${BINTRAY_API_KEY} \
 			-H "Content-Type: application/json" -d "{\"username\": \"${SONATYPE_USER_TOKEN}\", \"password\": \"${SONATYPE_PASSWORD_TOKEN}\"}" \
 			-f \
 			-X \
 			POST "https://api.bintray.com/maven_central_sync/${BINTRAY_SUBJECT}/${BINTRAY_REPO}/${groupId}/versions/${version}" > /dev/null || { echo "Failed to sync" >&2; exit 1; }
-echo "Sync complete"
+echo "Sync complete"