Release 2.1.0

What's Changed

• ENH: catch SSL error as well by @erfannariman in #93
• BUG: retry counter by @erfannariman in #94
• Incremental load by @melvinfolkers in #92
• Implement line_id in browse by @TimvdHeijden in #95
• new function for querying by year (fast way) by @melvinfolkers in #98
• add head.office if not present in dataset by @melvinfolkers in #99
• ENH: clean up login and create own exception by @erfannariman in #101
• CLN: Clean up exceptions and tests by @erfannariman in #102
• release 2.1.0-rc.5 by @erfannariman in #103
• Add error for access_token = None by @TimvdHeijden in #104
• Release 2.1.0 by @erfannariman in #105

Full Changelog: v2.0.5...v2.1.0