Update CHANGELOG.md

Merge pull request dbt-labs#309 from fishtown-analytics/bump/0.19.0

Allow dbt v0.19.0

Merge pull request dbt-labs#279 from fishtown-analytics/fix-default-args

Remove errant default args from get_tables_by_pattern_sql

Merge pull request dbt-labs#275 from fishtown-analytics/fix/bq-schema…

…-pattern

Handle schema pattern on BQ

Merge pull request dbt-labs#272 from fishtown-analytics/prepare-0.6.0…

…-release

Prepare 0.6.0 release

Merge pull request dbt-labs#263 from fishtown-analytics/prepare-0.5.1

Prepare for 0.5.1 release

Merge pull request dbt-labs#220 from fishtown-analytics/feature/get_r…

…elations_by_schema_prefix

feature/get relations by schema prefix

Ensure surrogate key handles single arg

Merge pull request dbt-labs#236 from fishtown-analytics/jtalmi-fix-in…

…sert-by-period

Return target relation in insert by period materialization

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