change capabilities to use w3c compliant prefixes

[titusfortner]

Change list

• updated mobile capabilities to use w3c compliant prefix appium:

Types of changes

What types of changes are you proposing/introducing to Java client?

• No changes in production code.
• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Details

This makes java-client compliant with required w3c syntax, which will likely be necessary when users update to Selenium 4.

The tests like startingAndroidAppWithCapabilitiesOnlyTest fail with this PR, but I would consider these more unit tests than user facing changes because no one should be checking the input to Capabilities with the output from the server.

That said, if we have #1319 we could override getCapability to add appium: if we need the inputs to match the outputs.

I also do not know if or how settings might need to be adjusted to ensure compatible versions of things are used.

[titusfortner]

(this is draft because I'm not sure how you want the tests handled, and if this should wait for #1319)

[mykola-mokhnach]

it makes sense to have a separate constant defined for appium:

[mykola-mokhnach]

I think we cannot merge this change yet, because it will break mjsonwp tests. Actually, it's the same reason we don't incorporate the alpha version of selenium 4 lib - users want to have stable releases rather than alpha snapshots.

[titusfortner]

Nevermind, you are automatically doing what is needed here:

java-client/src/main/java/io/appium/java_client/remote/NewAppiumSessionPayload.java

Lines 390 to 392 in 50e2318

	if (APPIUM_CAPABILITIES.contains(key) && !forceMobileJSONWP) {
	return APPIUM_PREFIX + key;
	}

and I just missed it.