chore(dependencies): use version 1.29 of org.yaml:snakeyaml to stay u…

…p to date (spinnaker#60)

Don't use anything newer (current latest is 1.33) due to
spring-projects/spring-boot#32228 (comment).

Note also that Salesforce clouddriver fails to start with 1.33 since clouddriver-local.yml
is bigger than the default 3MB limit that 1.32 introduces.  See
https://bitbucket.org/snakeyaml/snakeyaml/pull-requests/22.

@W-12038518

spinnaker-dependencies/spinnaker-dependencies.gradle

@@ -151,7 +151,7 @@ dependencies {
     api("org.objenesis:objenesis:2.5.1")
     api("org.pf4j:pf4j:3.2.0")
     api("org.pf4j:pf4j-update:2.3.0")
-    api("org.yaml:snakeyaml:1.33") // TODO: remove when spring boot brings in at least 1.33
+    api("org.yaml:snakeyaml:1.29") // safe to upgrade beyond 1.29 with spring boot >= 2.6.12.  See https://github.com/spring-projects/spring-boot/issues/32228#issue-1361858500.
     api("org.springdoc:springdoc-openapi-webmvc-core:${versions.openapi}")
     api("org.springdoc:springdoc-openapi-kotlin:${versions.openapi}")
     api("org.springframework.boot:spring-boot-configuration-processor:${versions.springBoot}")