Bump springdoc to 1.6.8

Also unify springdoc version in variable

Author: Brutus5000

build.gradle

@@ -239,12 +239,13 @@ dependencies {
 
   // Manually managed dependencies
   def elideVersion = "6.1.5"
+  def springdocVersion = "1.6.8"
   implementation("com.yahoo.elide:elide-core:${elideVersion}")
   implementation("com.yahoo.elide:elide-swagger:${elideVersion}")
   implementation("com.yahoo.elide:elide-datastore-jpa:${elideVersion}")
   implementation("com.yahoo.elide:elide-datastore-multiplex:${elideVersion}")
-  implementation("org.springdoc:springdoc-openapi-ui:1.6.7")
-  implementation("org.springdoc:springdoc-openapi-security:1.6.7")
+  implementation("org.springdoc:springdoc-openapi-ui:${springdocVersion}")
+  implementation("org.springdoc:springdoc-openapi-security:${springdocVersion}")
   implementation("com.github.FAForever:faf-java-commons:0e5d22ffff6e4dea81bac494d532627fcca8ebc4")
   implementation("org.kohsuke:github-api:1.306")
   implementation("org.eclipse.jgit:org.eclipse.jgit:6.1.0.202203080745-r")