[cmd/builder] Fix otelcol_version being ignored

[mx-psi]

Description:

Adds go.opentelemetry.io/collector/otelcol to go.mod template for the builder. This fixes #8692.

Since #8443, the otelcol folder is its own component. Before this change, otelcol_version was enforced by the collector module dependency:

opentelemetry-collector/cmd/builder/internal/builder/templates/go.mod.tmpl

Line 23 in 287b98f

go.opentelemetry.io/collector v{{.Distribution.OtelColVersion}}

After this change, the go mod tidy step here:

opentelemetry-collector/cmd/builder/internal/builder/main.go

Line 115 in 287b98f

cmd := exec.Command(cfg.Distribution.Go, "mod", "tidy", "-compat=1.20")

will add the latest available version for the otelcol module since none of the components actually depend on it. For example, with the v0.86.0 builder config the output is as follows:

❯ go mod tidy -v -compat=1.20
go: finding module for package go.opentelemetry.io/collector/otelcol
go: found go.opentelemetry.io/collector/otelcol in go.opentelemetry.io/collector/otelcol v0.87.0

Explicitly adding otelcol makes it so the otelcol_version is correctly honored.

Link to tracking Issue: Fixes #8692

[codecov]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Files	Coverage Δ
cmd/builder/internal/command.go	61.97% <0.00%> (-1.34%)	⬇️
cmd/builder/internal/builder/config.go	65.95% <45.45%> (-2.72%)	⬇️

📢 Thoughts on this report? Let us know!.

[codeboten]

Thanks for fixing @mx-psi