We have a liquibase command that looks something like this:

```sh
/liquibase/liquibase \
       --driver=org.postgresql.Driver \
       --changeLogFile="db.changelog-master.xml" \
       --url=<redacted> \
       --username=<redacted> \
       --password=<redacted> \
       update \
       -Dcoreschema="${core_schema}"
```

After upgrading the CLI from 4.3.3 to 4.4.0, it fails with the following error:

```
Unexpected argument(s): -Dcoreschema=public

For detailed help, try 'liquibase --help' or 'liquibase <command-name> --help'
```

Since the release notes state "this release should be 100% backwards compatible", I expect this is an oversight? Or is there a replacement for the `-Dproperty=value` syntax? I haven't found one looking through `--help` and the [property substitution docs](https://docs.liquibase.com/concepts/basic/changelog-property-substitution.html) at least.

The syntax can also still be found on https://docs.liquibase.com/tools-integrations/cli/home.html:

![image](https://user-images.githubusercontent.com/2620907/122090597-36d63400-ce08-11eb-92e8-d320cd5c5baa.png)


* @param paramName    name of the parameter
     * @param defaultValue return value if parameter is not given
     * @return the user-specified value for paramName, or defaultValue
     * @throws CommandLineParsingException if a parameter on the command line is un-parsable
     */
    private String getCommandParam(String paramName, String defaultValue) throws CommandLineParsingException {
        for (String param : commandParams) {
            if (!param.contains("=")) {
                continue;
            }
            String[] splitArg = splitArg(param);
            String attributeName = splitArg[0];
            String value = splitArg[1];
            if (attributeName.equalsIgnoreCase(paramName)) {
                return value;
            }
        }
        return defaultValue;
    }
    private Database createReferenceDatabaseFromCommandParams(
            Set<String> commandParams, ResourceAccessor resourceAccessor)
            throws CommandLineParsingException, DatabaseException {
        String refDriver = referenceDriver;
        String refUrl = referenceUrl;
        String refUsername = referenceUsername;
        String refPassword = referencePassword;
        String defSchemaName = this.referenceDefaultSchemaName;
        String defCatalogName = this.referenceDefaultCatalogName;
        for (String param : commandParams) {
            String[] splitArg = splitArg(param);