* Adds custom comparison for checking multiple substrings
This changeset introduces custom comparison for checking if a target
string has given multiple substrings, namely `ContainsMultipleSubstrings`.
Also removes `commands.TestContains` function and replaces all references
of `commands.TestContains` with `gotest.tools/assert.Check` function and
uses `ContainsMultipleSubstrings` as comparison function.
* Renames and makes the compare function variadic
New name: ContainsAll
New location: pkg/util/compare.go
Also the function now takes target string as first arg,
and accepts any number of substrings to check.
Removed the message arg, the compare function composes the error message.
For eg:
```
Actual output: foo-abcd foo <unknown> 0 OK / 0 <unknown> <unknown>
Missing strings: foo-abcd1, foo1
```
* Adds tests for compare utility ContainsAll
* Update vendor/modules.txt
- Accepts an argument name for listing particular route
- Enables the machine readable output flags
- Updates docs for kn route command group
- Adds unit tests for route command group and route list
- Adds integration tests for route list in basic workflow test
- Updates tests and getting namespace
- Adds more unit tests for code in pkg/kn/commands/route/list_flags.go
- Adds route list command in smoke tests
- Updates vendor/modules.txt
- Clean up imports
- Addresses review comments
- replaces knative to Knative
- uses reflect.DeepEqual for slice comparison
- removes few code comments
- removes irrelevant tests modifications from the PR