Build: Fix deb version to use tilde with prerelease versions

This commit converts the deb package to use tildes in place of dash in
the internal package version. This is only relevant for prerelease
versions of elasticsearch. Previously, this was not possible due to
problems with the underlying library used by the ospackage plugin, but
since a recent upgrade, it now works.

closes elastic#21139

distribution/packages/build.gradle

@@ -217,7 +217,7 @@ task buildDeb(type: Deb) {
   dependsOn processDebFiles
   configure(commonPackageConfig('deb'))
 
-  version = project.version
+  version = project.version.replace('-', '~')
   packageGroup 'web'
   requires 'bash'
   requires 'libc6'