Add Missing config file for code coverage (kserve#4581)

Signed-off-by: Andrews Arokiam <andrews.arokiam@ideas2it.com>

Author: andyi2it

.github/.testcoverage.yml

@@ -0,0 +1,53 @@
+# (mandatory) 
+# Path to coverage profile file (output of `go test -coverprofile` command).
+#
+# For cases where there are many coverage profiles, such as when running 
+# unit tests and integration tests separately, you can combine all those
+# profiles into one. In this case, the profile should have a comma-separated list 
+# of profile files, e.g., 'cover_unit.out,cover_integration.out'.
+profile: coverage.out
+
+# Holds coverage thresholds percentages, values should be in range [0-100].
+threshold:
+  # (optional; default 0) 
+  # Minimum coverage percentage required for individual files.
+  # file: 70
+
+  # (optional; default 0) 
+  # Minimum coverage percentage required for each package.
+  # package: 80
+
+  # (optional; default 0) 
+  # Minimum overall project coverage percentage required.
+  total: 80
+
+# Holds regexp rules which will override thresholds for matched files or packages 
+# using their paths.
+#
+# First rule from this list that matches file or package is going to apply 
+# new threshold to it. If project has multiple rules that match same path, 
+# override rules should be listed in order from specific to more general rules.
+# override:
+#   # Increase coverage threshold to 100% for `foo` package 
+#   # (default is 80, as configured above in this example).
+#   - path: ^pkg/lib/foo$
+#     threshold: 100
+
+# Holds regexp rules which will exclude matched files or packages 
+# from coverage statistics.
+exclude:
+  # Exclude files or packages matching their paths
+  paths:
+    - zz_generated.deepcopy.go
+    - openapi_generated.go
+    - testing
+    - pkg\\/client
+
+# File name of go-test-coverage breakdown file, which can be used to 
+# analyze coverage difference.
+breakdown-file-name: ''
+
+diff:
+  # File name of go-test-coverage breakdown file which will be used to 
+  # report coverage difference.
+  base-breakdown-file-name: ''