v0.21.0

v0.21.0

• Several optimizations result in roughly 5 - 10% faster reading of simtel files
• EventIOFile and EventIOObject act as true iterators now (do not reset int __iter__)
• Removed the hotfix for the memory leak for zstd files, as this was fixed upstream in version 0.11.1

Merged PRs:

• Merge pull request #177 from cta-observatory/update_readme
• Merge pull request #174 from cta-observatory/fix_iterators
• Merge pull request #176 from cta-observatory/remove_zstd_hotfix
• Merge pull request #175 from cta-observatory/gitignore
• Merge pull request #172 from cta-observatory/reorder_ifs
• Merge pull request #171 from cta-observatory/no_init_parsing