## Environment
**Liquibase Version**: org.liquibase:liquibase-core:jar:3.8.9

**Liquibase Integration & Version**: maven

**Database Vendor & Version**: postgres 11

**Operating System Type & Version**: ubuntu (wsl)

## Description
PrimaryKey constraint does not honor 'deferrable' and 'initiallyDeferred' settings so that created primary key is not 'deferred'

## Steps To Reproduce
Use script:

```
<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
                   xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
                   xmlns:pro="http://www.liquibase.org/xml/ns/pro"
                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                   xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-4.0.xsd http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.0.xsd">
    <changeSet author="author" id="some-id">  
        <createTable tableName="abc">
            <column name="id" type="INTEGER">
                <constraints nullable="false" primaryKey="true" primaryKeyName="abc_PK" deferrable="true" initiallyDeferred="true"/>
            </column>
        </createTable>
    </changeSet>
</databaseChangeLog>
```

## Actual Behavior
2020-12-18 09:01:19.936 [main] INFO  liquibase.executor.jvm.JdbcExecutor - CREATE TABLE public.abc (id INTEGER NOT NULL, CONSTRAINT "abc_PK" PRIMARY KEY (id))

## Expected/Desired Behavior
PRIMARY KEY is created with _deferrable initially deferred_


unnamedUniqueConstraints.add(uniqueConstraint);
            } else {
                String constraintName = uniqueConstraint.getConstraintName();
                UniqueConstraint existingConstraint = namedUniqueConstraints.get(constraintName);
                if (existingConstraint != null) {
                    if (uniqueConstraint.shouldValidateUnique()) {
                        
                        existingConstraint.setValidateUnique(true);
                    }
                    existingConstraint.getColumns().addAll(uniqueConstraint.getColumns());
                } else {
                    
                    namedUniqueConstraints.put(constraintName, uniqueConstraint);
                }
            }
        }
        unnamedUniqueConstraints.addAll(namedUniqueConstraints.values());
        for (UniqueConstraint uniqueConstraint : unnamedUniqueConstraints) {
            if (uniqueConstraint.getConstraintName() != null) {
                buffer.append(" CONSTRAINT ");
                buffer.append(database.escapeConstraintName(uniqueConstraint.getConstraintName()));
            }
            buffer.append(" UNIQUE (");
            buffer.append(database.escapeColumnNameList(StringUtil.join(uniqueConstraint.getColumns(), ", ")));
            buffer.append(")");
            if (database instanceof OracleDatabase) {
                buffer.append(!uniqueConstraint.shouldValidateUnique() ? " ENABLE NOVALIDATE " : "");
            }
            buffer.append(",");
        }