chore: Go mod & .gitignore

[candiduslynx]

Follow-up to #23

Additionally, you might want to loot at the type conversion from old types to the new ones.
I presume you used the types from Sharepoint, so Int32 instead of Int64 or Float32 instead of Float64 was a deliberate choice, but needed to highlight this code nonetheless.

[candiduslynx]

@koltyakov I've looked through the update to v4 you performed & it's a great job! Now the code allows to sync several tables of the same type in parallel, which what I wanted to address in #22.

I have only a small chore to update .gitignore & go.mod files to propose.
Additionally, see the link to the implementation of the type conversions we used in v2.