Enable BSP support for the repository.

Author: stuhood

Diff for: .gitignore

@@ -6,3 +6,7 @@
 
 # Editor specific files
 *.swp
+/.idea/
+
+# Written by the `./pants experimental-bsp` command on a user-by-user basis.
+/.bsp/

Diff for: bsp-groups.toml

@@ -0,0 +1,6 @@
+[groups.default]
+addresses = [
+  "src/jvm::",
+  "tests/jvm::",
+]
+resolve = "jvm:jvm-default"

Diff for: pants.toml

@@ -2,7 +2,7 @@
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
 [GLOBAL]
-pants_version = "2.11.0"
+pants_version = "2.13.0.dev0"
 backend_packages = [
   # This repository demonstrates a mix of Java and Scala, and so both backends are enabled. But each
   # backend can be used independently, so there is no need to expose Scala BUILD file
@@ -22,7 +22,13 @@ backend_packages = [
 # directory, organized by type.
 #
 # See https://www.pantsbuild.org/docs/source-roots for more information.
-root_patterns = ["/src/*"]
+root_patterns = [
+  "/src/*",
+  "/tests/*",
+]
+
+[experimental-bsp]
+groups_config_files = ["bsp-groups.toml"]
 
 [javac]
 args = [