[BUG] Decimal flag error

[engn33r]

Describe the bug
Getting an error when I use the --decimal flag

To Reproduce
Steps to reproduce the behavior:

1. Run: sothis --mode fast_track --source_rpc https://eth.llamarpc.com --contract_address 0xbebc44782c7db0a1a60cb6fe97d0b483032ff1c7 --storage_slot 80084422859880547211683076133703299733277748156566366325829078699459944778998 --origin_block 17750000 --terminal_block 17753000 --query_interval 100 --decimal --filename tripool_dai.json
2. When all the data has been queried from the specified blocks, this error message will appear when attempting to write the received data to the output file. No output file is created:
   Writing to file: ./tripool_dai.json thread 'main' panicked at 'called Result::unwrap()on anErrvalue: ParseIntError { kind: PosOverflow }', /home/user/.cargo/registry/src/index.crates.io-6f17d22bba15001f/sothis-0.5.0/src/tracker/common.rs:70:37 note: run withRUST_BACKTRACE=1 environment variable to display a backtrace
3. Run the same command as step 1 without the --decimal flag and observe no error

Expected behavior
No error. Output file contains data with decimal conversion.

[makemake-kbo]

At a glance it looks like the value is too big for u64::MAX

If so it should be a relatively simple fix