resource/aws_elasticache_parameter_group: Remove deprecated (helper/schema.ResourceData).Partial() and (helper/schema.ResourceData).SetPartial() (#12471)
resource/aws_elasticache_parameter_group: Remove deprecated (helper/schema.ResourceData).Partial() and (helper/schema.ResourceData).SetPartial() (#12471)

Reference: https://github.com/terraform-providers/terraform-provider-aws/issues/12083
Reference: https://github.com/terraform-providers/terraform-provider-aws/issues/12087

Previously:

```
aws/resource_aws_elasticache_parameter_group.go:136:2: R007: deprecated (schema.ResourceData).Partial
aws/resource_aws_elasticache_parameter_group.go:310:3: R008: deprecated (schema.ResourceData).SetPartial
aws/resource_aws_elasticache_parameter_group.go:313:2: R007: deprecated (schema.ResourceData).Partial
aws/resource_aws_elasticache_parameter_group.go:84:2: R007: deprecated (schema.ResourceData).Partial
aws/resource_aws_elasticache_parameter_group.go:85:2: R008: deprecated (schema.ResourceData).SetPartial
aws/resource_aws_elasticache_parameter_group.go:86:2: R008: deprecated (schema.ResourceData).SetPartial
aws/resource_aws_elasticache_parameter_group.go:87:2: R008: deprecated (schema.ResourceData).SetPartial
aws/resource_aws_elasticache_parameter_group.go:88:2: R007: deprecated (schema.ResourceData).Partial
```

Output from acceptance testing:

```
--- PASS: TestAccAWSElasticacheParameterGroup_Description (23.39s)
--- PASS: TestAccAWSElasticacheParameterGroup_basic (25.25s)
--- PASS: TestAccAWSElasticacheParameterGroup_UppercaseName (25.32s)
--- PASS: TestAccAWSElasticacheParameterGroup_removeReservedMemoryParameter (42.06s)
--- PASS: TestAccAWSElasticacheParameterGroup_removeAllParameters (44.50s)
--- PASS: TestAccAWSElasticacheParameterGroup_addParameter (44.70s)
--- PASS: TestAccAWSElasticacheParameterGroup_updateReservedMemoryParameter (90.73s)
--- PASS: TestAccAWSElasticacheParameterGroup_switchReservedMemoryParameter (91.11s)
```
kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws,terraform-providers/terraform-provider-aws,kjmkznr/terraform-provider-aws