[infra] Remove obsolete compose attribute (#6310)

Author: martincostello

build/docker-compose.net8.0.yml

@@ -1,5 +1,3 @@
-version: '3.7'
-
 services:
   tests:
     build:

build/docker-compose.net9.0.yml

@@ -1,5 +1,3 @@
-version: '3.7'
-
 services:
   tests:
     build:

examples/AspNetCore/docker-compose.yaml

@@ -1,4 +1,3 @@
-version: "3"
 services:
 
   # OTEL Collector to receive logs, metrics and traces from the application

examples/MicroserviceExample/docker-compose.yml

@@ -1,5 +1,3 @@
-version: '3.8'
-
 services:
   zipkin:
     image: openzipkin/zipkin

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/IntegrationTest/docker-compose.yml

@@ -2,8 +2,6 @@
 # This should be run from the root of the repo:
 #    docker compose --file=test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/IntegrationTest/docker-compose.yml --project-directory=. up --exit-code-from=tests --build
 
-version: '3.7'
-
 services:
   init-service:
     image: otel-test-image

test/OpenTelemetry.Instrumentation.W3cTraceContext.Tests/docker-compose.yml

@@ -1,7 +1,6 @@
 # Start a container and then run OpenTelemetry W3C Trace Context tests.
 # This should be run from the root of the repo:
 #  opentelemetry>docker compose --file=test/OpenTelemetry.Instrumentation.W3cTraceContext.Tests/docker-compose.yml --project-directory=. up --exit-code-from=tests --build
-version: '3.7'
 
 services:
   tests: