message: Use stringifyEntityRef in place of deprecated
diff: import {
  Entity,
  ENTITY_DEFAULT_NAMESPACE,
  - serializeEntityRef,
  + stringifyEntityRef,
  } from '@backstage/catalog-model';
  import { NotModifiedError } from '@backstage/errors';
  import {
  @@ -75,7 +75,7 @@ export class DocsBuilder {
  */
  this.logger.info(
  - `Step 1 of 3: Preparing docs for entity ${serializeEntityRef(
  + `Step 1 of 3: Preparing docs for entity ${stringifyEntityRef(
  this.entity,
  )}`,
  );
  @@ -116,7 +116,7 @@ export class DocsBuilder {
  // Set last check happened to now
  new BuildMetadataStorage(this.entity.metadata.uid).setLastUpdated();
  this.logger.debug(
  - `Docs for ${serializeEntityRef(
  + `Docs for ${stringifyEntityRef(
  this.entity,
  )} are unmodified. Using cache, skipping generate and prepare`,
  );
  @@ -126,7 +126,7 @@ export class DocsBuilder {
  }
  this.logger.info(
  - `Prepare step completed for entity ${serializeEntityRef(
  + `Prepare step completed for entity ${stringifyEntityRef(
  this.entity,
  )}, stored at ${preparedDir}`,
  );
  @@ -136,7 +136,7 @@ export class DocsBuilder {
  */
  this.logger.info(
  - `Step 2 of 3: Generating docs for entity ${serializeEntityRef(
  + `Step 2 of 3: Generating docs for entity ${stringifyEntityRef(
  this.entity,
  )}`,
  );
  @@ -176,7 +176,7 @@ export class DocsBuilder {
  */
  this.logger.info(
  - `Step 3 of 3: Publishing docs for entity ${serializeEntityRef(
  + `Step 3 of 3: Publishing docs for entity ${stringifyEntityRef(
  this.entity,
  )}`,
  );
  