Freshen the README

Author: mr-c

README.md

@@ -1,47 +1,70 @@
 # cwl-utils
 
-A collection of scripts to demonstrate the use of the [new Python classes for loading and parsing CWL v1.0 documents](https://github.com/common-workflow-language/cwl-utils/blob/master/cwl_utils/parser_v1_0.py).
-
-
-`cwl_utils/parser_v1_0.py` was created via
-`schema-salad-tool --codegen python https://github.com/common-workflow-language/common-workflow-language/raw/master/v1.0/CommonWorkflowLanguage.yml`
+A collection of scripts to demonstrate the use of the new Python classes for
+loading and parsing [CWL v1.0 ](https://github.com/common-workflow-language/cwl-utils/blob/main/cwl_utils/parser/v1_0.py),
+ [CWL v1.1](https://github.com/common-workflow-language/cwl-utils/blob/main/cwl_utils/parser/v1_1.py),
+and [CWL v1.2](https://github.com/common-workflow-language/cwl-utils/blob/main/cwl_utils/parser/v1_2.py)
+documents.
 
 ## Install
 
-Requires Python 3.6.x or Python 3.7
+Requires Python 3.6+
 
 ``` bash
-git clone https://github.com/common-workflow-language/cwl-utils.git
-virtualenv -p python3.6 venv3.6
+virtualenv -p python3.6 venv3.6  # Python 3.7, 3.8, or 3.9 would also work
 source venv3.6/bin/activate
 pip install cwl-utils
 ```
+or install the latest development version of `cwl-utils`
+
+``` bash
+git clone https://github.com/common-workflow-language/cwl-utils.git
+cd cwl-utils
+virtualenv -p python3.6 venv3.6  # Python 3.7, 3.8, or 3.9 would also work
+source venv3.6/bin/activate
+pip install .
+```
 
 ## Usage
 
-### Pull the image with Docker
+### Pull the all referenced software container images
 
-This is the default behaviour:
+`docker_extract.py` is useful to cache or pre-pull all software container images
+referenced in a CWL CommandLineTool or CWL Workflow (including all referenced
+CommandLineTools and sub-Workflows and so on).
+
+The default behaviour is to use the Docker engine to download and save the software
+container images in Docker format.
 
 ```bash
 python docker_extract.py DIRECTORY path_to_my_workflow.cwl
 ```
 
-### Pull the image with Singularity
+Or you can use the Singularity software container engine to download and save the
+software container images and convert them to the Singularity format at the same
+time.
 
 ```bash
 python docker_extract.py --singularity DIRECTORY path_to_my_workflow.cwl
 ```
 
-## Regenerate
+## Development
 
-To regenerate install `schema_salad` package and run:
+### Regenerate parsers
+
+To regenerate install the `schema_salad` package and run:
+
+`cwl_utils/parser_v1_0.py` was created via
+`schema-salad-tool --codegen python https://github.com/common-workflow-language/common-workflow-language/raw/main/v1.0/CommonWorkflowLanguage.yml`
+
+`cwl_utils/parser_v1_1.py` was created via
+`schema-salad-tool --codegen python https://github.com/common-workflow-language/cwl-v1.1/raw/main/CommonWorkflowLanguage.yml`
+
+`cwl_utils/parser_v1_2.py` was created via
+`schema-salad-tool --codegen python https://github.com/common-workflow-language/cwl-v1.2/raw/main/CommonWorkflowLanguage.yml`
 
-```
-schema-salad-tool --codegen python \
-    https://raw.githubusercontent.com/common-workflow-language/common-workflow-language/master/v1.0/CommonWorkflowLanguage.yml
-```
 
-## Release
+### Release
 
-To release CWLUtils, bump the version in `cwl_utils/__meta__.py`, and tag that commit with the new version. TravisCI should release that tag.
+To release CWLUtils, bump the version in `cwl_utils/__meta__.py`, and tag that
+commit with the new version. TravisCI should release that tag.