1.6.3: guzzle 7 support

Merge pull request #19 from lamoda/up_guzzle_version

fix guzzle version to 6.3 or 7.5

Fix MarkCode serializer

Merge pull request #17 from lamoda/fixMarkCodeSerializer

Fix MarkCode serializer

Add field markCode in Item

Merge pull request #16 from lamoda/feature/CORE-4962

Fix type MarkCode

Fix validation timestamp format

Merge pull request #13 from lamoda/feature/CORE-4425

#CORE-4425 Поправил формат поля timestamp

fix fiscalReceiptNumber

Merge pull request #12 from AdamSolaris/master

Fix Payload $fiscalReceiptNumber serialized type

Fix measure enum type

Merge pull request #11 from lamoda/fixMeasureType

Fix Unum Measure type

Delete Deprecated field base_name

Merge pull request #10 from lamoda/feature/deleteDeprecatedBaseName

Delete deprecated field of Correction base_name

Fix correction getter return type

Merge pull request #9 from lamoda/fixGetterCorrection

Fix Correction getCashier return type

Add correction method and dto

Merge pull request #8 from lamoda/feature/CORE-3376

Add method sell_correction for v4 and v5

Fix: Validation fix

Merge pull request #7 from lamoda/fixValidationClient

Fix validation and add use Serializer