CompilerError - Stack too deep when compiling inline assembly: Variable headStart is 1 slot(s) too deep inside the stack  (Uniswap V3)

When try to complie base86.sol in Uniswap v3 .

solidity version 0.7.6

Complie Error comes up with : 

> Compiling base64-sol/base64.sol

**CompilerError: Stack too deep when compiling inline assembly: Variable headStart is 1 slot(s) too deep inside the stack.**
