Need to figure out publishing plugin incompaibility with 6.0.0 shadow plugin

[harshavardhana]

with version

git diff
diff --git a/build.gradle b/build.gradle
index 25fbe6ce..5120231f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -19,7 +19,7 @@
 /***************************/
 
 plugins {
-  id "com.github.johnrengelman.shadow" version "5.2.0"
+  id "com.github.johnrengelman.shadow" version "6.0.0"
   id "com.github.spotbugs" version "4.5.0"
   id "io.codearte.nexus-staging" version "0.22.0"
   id "de.marcphilipp.nexus-publish" version "0.4.0"

~  ./gradlew publishMavenJavaPublicationToMavenLocal
> Task :api:publishMavenJavaPublicationToMavenLocal FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':api:publishMavenJavaPublicationToMavenLocal'.
> Failed to publish publication 'mavenJava' to repository 'mavenLocal'
   > Invalid publication 'mavenJava': multiple artifacts with the identical extension and classifier ('jar', 'all').

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD FAILED in 8s
9 actionable tasks: 8 executed, 1 up-to-date

maven publication fails, whereas with 5.2.0 it works fine

~  ./gradlew publishMavenJavaPublicationToMavenLocal

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.6.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 2s
9 actionable tasks: 4 executed, 5 up-to-date

[balamurugana]

The issue is tracked at marcphilipp/nexus-publish-plugin#49