chore: revert adding of delete field to schema

[gmaclennan]

The delete field does not actually belong in the indexer, since it does
not change indexer behaviour in any way. Fixes #19

This reverts commit e617aa0.

[github-actions]

Pull Request Test Coverage Report for Build 6600851034

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 6381615774:	0.0%
Covered Lines:	328
Relevant Lines:	328

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 6600851034

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

---

Totals
Change from base Build 6381615774:	0.0%
Covered Lines:	328
Relevant Lines:	328

---

💛 - Coveralls