fix syntax

.github/scripts/psycopg2-check.sh

@@ -3,7 +3,7 @@ source venv/bin/activate
 python -m pip install .
 
 if [[ "$PSYCOPG2_WORKAROUND" == true ]]; then
-    if [[ pip show psycopg2-binary ]]; then
+    if [[ $(pip show psycopg2-binary) ]]; then
         PSYCOPG2_VERSION=$(pip show psycopg2-binary | grep Version | cut -d " " -f 2)
         pip uninstall -y psycopg2-binary
         pip install psycopg2==$PSYCOPG2_VERSION

README.md

@@ -26,7 +26,7 @@ more information on using dbt with Postgres, consult [the docs](https://docs.get
 By default, `dbt-postgres` installs `psycopg2-binary`. This is great for development, and even testing, as it does not require any OS dependencies; it's a pre-built wheel. However, building `psycopg2` from source will grant performance improvements that are desired in a production environment. In order to install `psycopg2`, use the following steps:
 
 ```bash
-if [[ pip show psycopg2-binary ]]; then
+if [[ $(pip show psycopg2-binary) ]]; then
     PSYCOPG2_VERSION=$(pip show psycopg2-binary | grep Version | cut -d " " -f 2)
     pip uninstall -y psycopg2-binary
     pip install psycopg2==$PSYCOPG2_VERSION