Replaced usage of format_ with schema_version in BuildInfo.
Replaced usage of format_ with schema_version in BuildInfo.
repod/files/buildinfo.py: Replace uses of FormatV1, FormatV2 with SchemaVersionV1, SchemaVersionV2. Delete the Format classes.
repod/repo/management/outputpackage.py: Replace uses of FormatV1, FormatV2 with SchemaVersionV1, SchemaVersionV2. Delete the Format classes.
tests/conftest.py: Update buildinfo test data, replacing "format" with "schema_version".
tests/files/test_buildinfo.py: Remove tests which test FormatV1, FormatV2.