Bump Google.Protobuf from 3.11.4 to 3.15.0 in /src/OrderBooks.Client#1

dependabot[bot] wants to merge 1 commit intomasterswisschain/Service.OrderBooks:masterfrom

dependabot/nuget/src/OrderBooks.Client/Google.Protobuf-3.15.0swisschain/Service.OrderBooks:dependabot/nuget/src/OrderBooks.Client/Google.Protobuf-3.15.0Copy head branch name to clipboard