Handle multiple types in coveralls.multiple when --umbrella is present

[pablocostass]

When the --umbrella flag isn't passed, excoveralls actually knows how to handle multiple types (it invokes ExCoveralls.analyze/3 for each of them), but if the option is present, then we handle the types as if it were only one

excoveralls/lib/excoveralls.ex

Lines 61 to 69 in e9776c9

	if options[:umbrella] do
	store_stats(stats, options, compile_path)
	else
	types = List.wrap(options[:type] || "local")
	stats = Stats.update_paths(stats, options)
	# Push all available options down
	options = options ++ opts
	Enum.each(types, &analyze(stats, &1, options))

This results in a function clause error, which can be replicated in the umbrella example repo, https://github.com/parroty/excoveralls_umbrella

excoveralls_umbrella on  master [!] via 💧 v1.18.2
➜ mix coveralls.multiple --umbrella --type html --type cobertura
==> subapp0
Running ExUnit with seed: 57138, max_cases: 24

..
Finished in 0.00 seconds (0.00s async, 0.00s sync)
2 tests, 0 failures
==> subapp1
Running ExUnit with seed: 57138, max_cases: 24

.
Finished in 0.00 seconds (0.00s async, 0.00s sync)
1 test, 0 failures
** (RuntimeError) Undefined type (htmlcobertura) is specified for ExCoveralls
    (excoveralls 0.18.5) lib/excoveralls.ex:157: ExCoveralls.analyze/3
    (mix 1.18.2) lib/mix/task.ex:495: anonymous fn/3 in Mix.Task.run_task/5
    (mix 1.18.2) lib/mix/cli.ex:107: Mix.CLI.run_task/2
    /Users/pablocostass/code/other/elixir/bin/mix:2: (file)
    (elixir 1.18.2) lib/code.ex:1525: Code.require_file/2

With the fix, however, one gets the following output

excoveralls_umbrella on  master [!] via 💧 v1.18.2
➜ mix coveralls.multiple --umbrella --type html --type cobertura
==> subapp0
Running ExUnit with seed: 860797, max_cases: 24

..
Finished in 0.00 seconds (0.00s async, 0.00s sync)
2 tests, 0 failures
==> subapp1
Running ExUnit with seed: 860797, max_cases: 24

.
Finished in 0.00 seconds (0.00s async, 0.00s sync)
1 test, 0 failures
----------------
COV    FILE                                        LINES RELEVANT   MISSED
100.0% apps/subapp0/lib/subapp0.ex                     9        2        0
 50.0% apps/subapp1/lib/subapp1.ex                     9        2        1
[TOTAL]  75.0%
----------------
Generating report...
Saved to: cover/