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**Apache Airflow version**: 2.0.1


**Environment**:

- **Cloud provider or hardware configuration**: MacBook Pro
- **OS** (e.g. from /etc/os-release): Catalina 10.15.7
- **Kernel** (e.g. `uname -a`): Darwin CSchillebeeckx-0589.local 19.6.0 Darwin Kernel Version 19.6.0: Thu Oct 29 22:56:45 PDT 2020; root:xnu-6153.141.2.2~1/RELEASE_X86_64 x86_64
- **Install tools**: pip

requirements.txt
```
apache-airflow[crypto,celery,amazon,mysql,jdbc,password,redis,slack,snowflake,ssh,google,databricks,mongo,zendesk,papermill,salesforce]==2.0.1
pyarrow==0.17.1
iniconfig==1.1.1
sqlparse==0.4.1
google-api-python-client===1.12.8
google-auth==1.27.0
google-api-core==1.26.0
avro-python3==1.10.0
databricks-connect==7.3.8
matplotlib==3.3.4
scikit-learn==0.24.1
ipykernel==5.4.3
flower==0.9.7

```

**What happened**:

I'm using MySQL as a backend and am using the `GoogleBaseHook`; when I run the webserver I see:
```
webserver_1  | [2021-02-16 23:39:13,008] {providers_manager.py:299} WARNING - Exception when importing 'airflow.providers.google.cloud.hooks.cloud_sql.CloudSQLHook' from 'apache-airflow-providers-google' package: No module named 'airflow.providers.postgres'
webserver_1  | [2021-02-16 23:39:13,009] {providers_manager.py:299} WARNING - Exception when importing 'airflow.providers.google.cloud.hooks.cloud_sql.CloudSQLDatabaseHook' from 'apache-airflow-providers-google' package: No module named 'airflow.providers.postgres'
webserver_1  | [2021-02-16 23:39:13,066] {providers_manager.py:299} WARNING - Exception when importing 'airflow.providers.google.cloud.hooks.cloud_sql.CloudSQLHook' from 'apache-airflow-providers-google' package: No module named 'airflow.providers.postgres'
webserver_1  | [2021-02-16 23:39:13,067] {providers_manager.py:299} WARNING - Exception when importing 'airflow.providers.google.cloud.hooks.cloud_sql.CloudSQLDatabaseHook' from 'apache-airflow-providers-google' package: No module named 'airflow.providers.postgres'
```

If I add the extra package `postgres` the warnings are not present anymore.


**What you expected to happen**:

No warnings

**How to reproduce it**:
<!---

As minimally and precisely as possible. Keep in mind we do not have access to your cluster or dags.

If you are using kubernetes, please attempt to recreate the issue using minikube or kind.

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- Kind https://kind.sigs.k8s.io/docs/user/quick-start/

If this is a UI bug, please provide a screenshot of the bug or a link to a youtube video of the bug in action

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--->


**Anything else we need to know**:

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airflow/providers_manager.py
"""Lazy initialization of provider data."""
        
        
        
        
        
        if self._initialized:
            return
        
        
        
        
        self._discover_all_airflow_builtin_providers_from_local_sources()
        self._discover_all_providers_from_packages()
        self._discover_hooks()
        self._provider_dict = OrderedDict(sorted(self._provider_dict.items()))  
        self._hooks_dict = OrderedDict(sorted(self._hooks_dict.items()))  
        self._connection_form_widgets = OrderedDict(sorted(self._connection_form_widgets.items()))  
        self._field_behaviours = OrderedDict(sorted(self._field_behaviours.items()))  
        self._discover_extra_links()
        self._initialized = True
    def _discover_all_providers_from_packages(self) -> None: