Avoid compiler warning in esp32 3.1.0

Avoid overloaded-virtual warning when compiled with All warnings. 

warning: 'virtual size_t Print::write(const uint8_t*, size_t)' was hidden [-Woverloaded-virtual=]
   64 |   virtual size_t write(const uint8_t *buffer, size_t size);
 by
note:   by 'SARA_R5::write'
  707 |   virtual size_t write(const char *buffer, size_t size);

Author: mazgch

src/SparkFun_u-blox_SARA-R5_Arduino_Library.h

@@ -705,6 +705,7 @@ class SARA_R5 : public Print
   virtual size_t write(uint8_t c);
   virtual size_t write(const char *str);
   virtual size_t write(const char *buffer, size_t size);
+  using Print::write;
 
   // General AT Commands
   SARA_R5_error_t at(void);