Update shadow plugin 6.1.0 -> 7.1.1

Version 7.1.1 is absent in jcenter, so additional repository was added
in some modules.

Leave old version in NewMultiplatformIT.kt because of
`This version of Shadow supports Gradle 7.0+ only. Please upgrade.` error.

^KTI-733 Fixed

gradle/versions.properties

@@ -24,7 +24,7 @@ versions.lz4-java=1.7.1
 versions.org.junit.platform=1.7.0
 versions.oro=2.0.8
 versions.serviceMessages=2019.1.4
-versions.shadow=6.1.0
+versions.shadow=7.1.1
 versions.streamex=0.7.2
 versions.trove4j=1.0.20200330