[DCJ-400] #major pre-releases use -snapshot suffix

Such as the client builds generated as part of PR commits.

Many Terra services use Dependabot to automate dependency upgrades.
Dependabot will ignore new versions with `-snapshot` suffix and rightfully interpret them as prereleases.

Also tagging this as a major release to bring Sam client versions up to 1.0.0, past older versions pre-semver.  My earlier attempt to do so did not properly trigger client publication on account of being a no-code commit.

codegen_java/project/Version.scala

@@ -15,8 +15,6 @@ object Version {
 
     // The project isSnapshot string passed in via command line settings, if desired.
     val isSnapshot = sys.props.getOrElse("project.isSnapshot", "true").toBoolean
-
-    // For now, obfuscate SNAPSHOTs from sbt's developers: https://github.com/sbt/sbt/issues/2687#issuecomment-236586241
-    if (isSnapshot) s"$semVer-SNAP" else semVer
+    if (isSnapshot) s"$semVer-snapshot" else semVer
   }
 }

codegen_java_old/project/Version.scala

@@ -15,8 +15,6 @@ object Version {
 
     // The project isSnapshot string passed in via command line settings, if desired.
     val isSnapshot = sys.props.getOrElse("project.isSnapshot", "true").toBoolean
-
-    // For now, obfuscate SNAPSHOTs from sbt's developers: https://github.com/sbt/sbt/issues/2687#issuecomment-236586241
-    if (isSnapshot) s"$semVer-SNAP" else semVer
+    if (isSnapshot) s"$semVer-snapshot" else semVer
   }
 }