Tomlplusplus Initial Integration (#11244)

The harness and build.sh have already been integrated into master, as
seen in this [PR](https://github.com/marzer/tomlplusplus/pull/214).

This pull request solely adds the necessary Dockerfile

projects/tomlplusplus/Dockerfile

@@ -0,0 +1,23 @@
+# Copyright 2023 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+FROM gcr.io/oss-fuzz-base/base-builder
+RUN apt-get update && apt-get install -y cmake make
+
+RUN git clone --depth 1 https://github.com/marzer/tomlplusplus.git tomlplusplus \
+        && cp tomlplusplus/fuzzing/build.sh $SRC/
+WORKDIR tomlplusplus
+