added readme for script

Author: lm1nrt

scripts/README.md

@@ -0,0 +1,61 @@
+# Update/create scala_x_x.bzl repository file script
+
+- [About](#about)
+- [Usage](#usage)
+- [Examples](#examples)
+- [Debugging](#debugging)
+- [Requirements](#requirements)
+
+### About
+The script allows to update a certain scala_x_x.bzl file and its content (artifact, sha, dependencies), by changing the value of `root_scala_version` variable.
+It can be used to create non-existent file for chosen Scala version. <br>
+It's using a [https://get-coursier.io/docs/](coursier) in order to **resolve** lists the transitive dependencies of dependencies and **fetch** the JARs of it.
+
+### Usage
+Usage from `/rules_scala/scripts`:
+````
+python3 create_repository.py
+````
+
+### Examples
+Current value of `root_scala_versions`:
+```
+root_scala_versions = ["2.11.12", "2.12.19", "2.13.14", "3.1.3", "3.2.2", "3.3.3", "3.4.3", "3.5.0"]
+```
+
+To **update** content of `scala_3_4.bzl` file:
+```
+root_scala_versions = ["2.11.12", "2.12.19", "2.13.14", "3.1.3", "3.2.2", "3.3.3", "3.4.4", "3.5.0"]
+                                                                                   ^^^^^^^ <- updated version
+```
+
+To **create** new `scala_3_6.bzl` file:
+```
+root_scala_versions = ["2.11.12", "2.12.19", "2.13.14", "3.1.3", "3.2.2", "3.3.3", "3.4.3", "3.5.0", "3.6.0"]
+                                                                                                     ^^^^^^^ <- new version
+```
+
+### Debugging
+Certain dependency version may not have a support for chosen Scala version e.g.
+```
+kind_projector_version = "0.13.2" if scala_major < "2.13" else "0.13.3"
+```
+
+In order of that, there may be situations that script won't work. To debug that problem and adjust the values of hard-coded variables:
+```
+scala_test_major = "3" if scala_major >= "3.0" else scala_major
+scala_fmt_major = "2.13" if scala_major >= "3.0" else scala_major
+kind_projector_version = "0.13.2" if scala_major < "2.13" else "0.13.3"
+f"org.scalameta:scalafmt-core_{scala_fmt_major}:{"2.7.5" if scala_major == "2.11" else scala_fmt_version}"
+```
+there is an option to print the output of these two subprocesses:
+
+`output = subprocess.run(f'cs fetch {artifact}', capture_output=True, text=True, shell=True).stdout.splitlines()` <br>
+
+```
+  command = f'cs resolve {' '.join(root_artifacts)}'
+  output = subprocess.run(command, capture_output=True, text=True, shell=True).stdout.splitlines()
+```
+
+### Requirements
+Installed [Coursier](https://get-coursier.io/) and [Python 3](https://www.python.org/downloads/)