ci: Upgrade Pants to 2.21.0.dev5 and remove no longer used ruff_previ…

…ew plugin (#2006)

README.md

@@ -268,12 +268,12 @@ or native SSH connection to kernels via our client SDK or desktop apps.
 Python Version Compatibility
 ----------------------------
 
-| Backend.AI Core Version | Compatible Python Version |
-|:-----------------------:|:-------------------------:|
-| 24.03.x / 24.09.x       | 3.12.x                    |
-| 23.03.x / 23.09.x       | 3.11.x                    |
-| 22.03.x / 22.09.x       | 3.10.x                    |
-| 21.03.x / 21.09.x       | 3.8.x                     |
+| Backend.AI Core Version | Python Version | Pantsbuild version |
+|:-----------------------:|:--------------:|:------------------:|
+| 24.03.x / 24.09.x       | 3.12.x         | 2.21.x             |
+| 23.03.x / 23.09.x       | 3.11.x         | 2.19.x             |
+| 22.03.x / 22.09.x       | 3.10.x         |                    |
+| 21.03.x / 21.09.x       | 3.8.x          |                    |
 
 
 License

pants.toml

@@ -1,5 +1,5 @@
 [GLOBAL]
-pants_version = "2.21.0.dev4"
+pants_version = "2.21.0.dev5"
 pythonpath = ["%(buildroot)s/tools/pants-plugins"]
 backend_packages = [
     "pants.backend.python",
@@ -10,7 +10,6 @@ backend_packages = [
     "pants.backend.experimental.python.lint.ruff.format",
     "pants.backend.experimental.visibility",
     "pants.backend.plugin_development",
-    # "ruff_preview",  # a vendored backport of the pants 2.20's lint plugin
     "setupgen",
     "platform_resources",
     "scie",
@@ -115,4 +114,4 @@ install_from_resolve = "mypy"
 install_from_resolve = "towncrier"
 
 [setuptools]
-install_from_resolve = "setuptools"
+install_from_resolve = "setuptools"