MINOR: [Docs] Fix number of minor format versions since 1.0.0

[ianmcook]

Fixes a minor docs omission from #43976.

[kou]

+1

[conbench-apache-arrow]

After merging your PR, Conbench analyzed the 4 benchmarking runs that have been run so far on merge-commit ee18860.

There were 4 benchmark results indicating a performance regression:

• Commit Run on amd64-m5-4xlarge-linux at 2024-09-19 00:56:05Z
  • dataset-serialize (Python) with dataset=nyctaxi_multi_ipc_s3, format=csv, selectivity=10pc
  • dataset-serialize (Python) with dataset=nyctaxi_multi_parquet_s3, format=csv, selectivity=100pc
• and 2 more (see the report linked below)

The full Conbench report has more details. It also includes information about 291 possible false positives for unstable benchmarks that are known to sometimes produce them.