Do not delete provider custom workflows in make ci-mgmt (#1068)

We introduced a notion of provider-custom workflow files, such as:

    aws-upstream-tests.yml

Currently CI knows to not delete them, but `make ci-mgmt` target still
does. This PR fixes this so that `make ci-mgmt`
target matches the behavior of CI workflows.

provider-ci/internal/pkg/templates/bridged-provider/Makefile

@@ -208,7 +208,7 @@ bin/pulumi-java-gen: .pulumi-java-gen.version
 # - Run make ci-mgmt to apply the change locally.
 #
 ci-mgmt: .ci-mgmt.yaml
-	rm -f .github/workflows/*.yml # Copied from update-workflows.yml
+	find .github/workflows/*.yml -type f ! -name "$(PACK)*.yml" -delete
 	go run github.com/pulumi/ci-mgmt/provider-ci@master generate \
 		--name $(ORG)/pulumi-$(PACK) \
 		--out . \

provider-ci/test-providers/acme/Makefile

@@ -174,7 +174,7 @@ bin/pulumi-java-gen: .pulumi-java-gen.version
 # - Run make ci-mgmt to apply the change locally.
 #
 ci-mgmt: .ci-mgmt.yaml
-	rm -f .github/workflows/*.yml # Copied from update-workflows.yml
+	find .github/workflows/*.yml -type f ! -name "$(PACK)*.yml" -delete
 	go run github.com/pulumi/ci-mgmt/provider-ci@master generate \
 		--name $(ORG)/pulumi-$(PACK) \
 		--out . \

provider-ci/test-providers/aws/Makefile

@@ -189,7 +189,7 @@ bin/pulumi-java-gen: .pulumi-java-gen.version
 # - Run make ci-mgmt to apply the change locally.
 #
 ci-mgmt: .ci-mgmt.yaml
-	rm -f .github/workflows/*.yml # Copied from update-workflows.yml
+	find .github/workflows/*.yml -type f ! -name "$(PACK)*.yml" -delete
 	go run github.com/pulumi/ci-mgmt/provider-ci@master generate \
 		--name $(ORG)/pulumi-$(PACK) \
 		--out . \

provider-ci/test-providers/cloudflare/Makefile

@@ -178,7 +178,7 @@ bin/pulumi-java-gen: .pulumi-java-gen.version
 # - Run make ci-mgmt to apply the change locally.
 #
 ci-mgmt: .ci-mgmt.yaml
-	rm -f .github/workflows/*.yml # Copied from update-workflows.yml
+	find .github/workflows/*.yml -type f ! -name "$(PACK)*.yml" -delete
 	go run github.com/pulumi/ci-mgmt/provider-ci@master generate \
 		--name $(ORG)/pulumi-$(PACK) \
 		--out . \

provider-ci/test-providers/docker/Makefile

@@ -179,7 +179,7 @@ bin/pulumi-java-gen: .pulumi-java-gen.version
 # - Run make ci-mgmt to apply the change locally.
 #
 ci-mgmt: .ci-mgmt.yaml
-	rm -f .github/workflows/*.yml # Copied from update-workflows.yml
+	find .github/workflows/*.yml -type f ! -name "$(PACK)*.yml" -delete
 	go run github.com/pulumi/ci-mgmt/provider-ci@master generate \
 		--name $(ORG)/pulumi-$(PACK) \
 		--out . \