Add CPubKey m_public_key to Project class for v2

This is for future use.

src/gridcoin/project.h

@@ -10,6 +10,7 @@
 #include "gridcoin/contract/handler.h"
 #include "gridcoin/contract/payload.h"
 #include "serialize.h"
+#include "pubkey.h"
 
 #include <memory>
 #include <vector>
@@ -58,6 +59,7 @@ class Project : public IContractPayload
  std::string m_url; //!< As it exists in the contract value field.
  int64_t m_timestamp; //!< Timestamp of the contract.
  bool m_gdpr_controls; //!< Boolean to indicate whether project has GDPR stats export controls.
+ CPubKey m_public_key; //!< Project public key.
 
  //!
  //! \brief Initialize an empty, invalid project object.
@@ -187,6 +189,7 @@ class Project : public IContractPayload
 
  if (m_version >= 2) {
  READWRITE(m_gdpr_controls);
+ READWRITE(m_public_key);
  }
  }
  }