paramgen: 'index out of range' with invalid tag on embeded struct field

[hariso]

Bug description

paramgen panics with index out of range if a field in an embedded struct has an invalid tag (for example, a validation tag).

Steps to reproduce

Save the following into a file in a directory called invalid3, and run go mod init example.com/invalid3:

package invalid3

type Config struct {
	AnotherConfig

	Param1 string
}

type AnotherConfig struct {
	AnotherParam string `json:"anotherParam" validate:"inclusion=foo,bar"`
}

Run the following tests:

// Fails with:
// panic: runtime error: index out of range [0] with length 0 [recovered]
func TestConfig(t *testing.T) {
	is := is.New(t)
	_, _, err := ParseParameters("./invalid3", "Config")
	is.NoErr(err)
}

// Fails with:
// err: [parseStructType] error parsing field "AnotherParam": [parseField] [parseIdent] invalid tag format
func TestAnotherConfig(t *testing.T) {
	is := is.New(t)
	_, _, err := ParseParameters("./invalid3", "AnotherConfig")
	is.NoErr(err)
}

Version

SDK version v0.7.2